
Stupidity: So when Belle finds out that her father is being hauled away to the insane asylum, she is in such a rush to get that she doesn't even change out of the massive yellow dress that would be really uncomfortable to ride a horse in, probably because she is in such a hurry. But earlier in the movie, the Beast shows her his magic book that allows him to teleport anywhere in the world, so why doesn't she just use that?
Suggested correction: As you've just stated, she is in a hurry. She probably didn't think about using the book.

Stupidity: When the invasion of planet P begins, we see the Rodger Young get hit. In the explosion sequence, we are treated to people sitting around tables in what can only be described as a mess hall exploding. In a military environment, this would be a time where everyone would be at their "battle stations". Nobody would be having chow or off-time when the ship is expecting combat. In this case, it was a planned troop landing.
Suggested correction: Yes, it was stupidity, but it was an intentional depiction that supports the plot. During the landing, the Captain is completely surprised by the bombardment and says something like, "This isn't light uncoordinated resistance." The fleet's lack of preparedness at Planet P is a major plot point that later results in the replacement of the Air Marshal in command.
No, you are talking about a different sequence. When they are unprepared, they are doing an invasion of Klendathu, the Bug's home planet. This is earlier in the movie and the Rodger Young was only slightly damaged in that. The stupidity is about the invasion of Planet P at the end of the movie, where the Rodger Young is cut in half.

Stupidity: When Jasmine finds out that Prince Ali is actually the boy she met in the marketplace, she seems to completely forget about Jafar telling her he had been executed. She never asks why he's alive, nor does she even bother to confront Jafar about his treachery.
Suggested correction: The fact Aladdin was alive only told her Jafar lied about it. When she is brought back by Aladdin to the palace it is still night, not long after that she is confronted by her father and Jafar who has him under a spell. She hardly had time to ask about the treachery, probably thinking to do it in the morning. It is there and then Jafar is exposed by Aladdin. She probably wondered about it, but didn't figure out the implications yet.

Stupidity: Early in the film, Peter Parker desperately wants to see Mary Jane's performance, but he is turned away at the theatre doors because he is a few minutes late. Defeated, Peter shuffles away and sulks. Seriously? Why couldn't Peter simply enter the theatre through a side door or the roof? He's Spider Man.
Suggested correction: There's two things to consider here. First, a major theme of the film is Peter struggling with keeping his Spider-Man and Peter Parker lives separate. Peter makes every attempt to get to the show on his own, as Peter by riding on his scooter. Simply breaking into the theater after he has been turned away would ruin the idea that keeping his two lives separate is a struggle. It would instead imply the opposite, that Peter can simply use his powers to solve his problems whenever it's convenient. Secondly, the usher makes it clear that no-one is to be admitted after the show has started as this would disturb the guests and possibly the performers as well. Sneaking into the theater could very well ruin the performance and Peter obviously wouldn't want that.
If there's one thing we know about Spider-Man, it's that he is incredibly stealthy, often coming and going without any detection whatsoever. He could have easily accessed the building and watched the show from a secluded vantage and even met Mary Jane backstage afterwards. Certainly in this case, using his powers would be justified, given that it was more important for Mary Jane to know Peter attended the show, rather than simply giving up.
He doesn't want to do any of that, though. He wants to go to the show as Peter, with a ticket, sit in a seat with the rest of the people, enjoy the show, and see Mary Jane afterwards. He stops the car chase as Spider-Man after his scooter is wrecked and instead of web-swinging to the theater, which would have been much faster, he chooses to change back into his regular clothes and drive the criminal's car. Sure, he certainly could have used his powers to get into the theater but the point is he doesn't want to. The fact that he chooses not to use his powers and instead deal with the consequences of hurting Mary Jane's feelings is the entire point.
And besides he'd probably get kicked out of the theater if he was caught.

Stupidity: Hans keeps a major part of his plan secret from his own team: that the electromagnetic lock will be disabled if the FBI shuts down power to the building. The mercenaries hired as muscle don't need to know the minutiae of the plan, but it seems ludicrous that Theo wasn't told. Theo states on more than one occasion that he can't proceed past a certain point and that he hopes Hans has a plan for the final lock. Evidently, Hans was keeping this information secret simply to amuse himself, which makes little sense considering how much planning went into the heist.
Suggested correction: Or because he simply doesn't trust anyone with that kind of knowledge. He neither trusts them or cares about them, it's all him.
So he trusts that Theo would be on board with all the murder and mayhem, open all the other locks, be in a tactical lookout position when the police try to breach, and drive the getaway vehicle. But he doesn't trust Theo enough to tell him the last lock will open when the power goes out?
It's not about trust; Hans needs Theo to do what he is there for and that is all you mention up to the final lock. He has a plan for the final lock and so there's no need to discuss it with the team, since it won't be any of them responsible.
The more people that know the plan the more chances of someone talking. Especially when they are hired mercenaries.
Theo was already on board with taking hostages and committing murder. Him knowing that the power needed to be shut off to open the last lock doesn't appear to be particularly important information you would need to keep from someone to keep them from talking.
If he's the only one that knows the final step to get the money, then at least up until that moment he is absolutely indispensable to the plan and ensures no-one would double-cross him. In any case I'm not sure being more cautious than necessary really qualifies as "stupidity."

Stupidity: There is no way a fighter with a brain would risk serious injury to themselves before a fight by continually punching a frozen rack of meat in a freezer slaughterhouse. There is nothing to gain by doing this, and it would only result in both fists being broken.
Suggested correction: In fact, Sylvester Stallone permanently damaged his knuckles filming the two scenes. He obviously did not realise how dangerous punching a side of beef would be, and it isn't out of the question that the character Rocky Balboa wouldn't realise this either.
It shouldn't take a rocket scientist to know that if you punch or hit anything with a bare fist against anything solid, rock hard, you will damage yourself badly.
Absolutely, it shouldn't, but that is not what the "Stupidity" category is for. It is unintelligent for someone to do this, but that is not a movie mistake. Sylvester Stallone really did punch that beef and really did injure himself, so it is not something that is out of the question for a character in a movie to do.
No, but it is out of the question for a man with painfully damaged knuckles to go fifteen rounds with a world heavyweight champion boxer. In fact, Rocky would probably have failed the compulsory pre-fight physical and would have been ruled unfit to fight.
Where in the movie is Rocky experiencing "painfully damaged knuckles"? With your logic, the fight would have most likely been called long before the 15th round, due to the very unrealistic and improbable punishment the 2 boxers were inflicting on each other.

Stupidity: The eco-terrorists leave the Orca completely unattended allowing Madison to take it without anyone realizing until she is long gone. In addition, they don't post any guards at the exit of the bunker and Madison simply walks away without anyone noticing her at all.
Suggested correction: They leave the Orca in their empty command room within a bunker filled with loyal men. There is no way anyone could have broken in and stolen it. Madison had the advantage of already being in the bunker and even then had to navigate through the air ducts in order to steal the Orca and escape. They wouldn't have armed men visible immediately outside because they didn't want anyone to notice that they were there.
Either one of these issues by themselves wouldn't be particularly stupid but the combination of them both would indeed allow someone to just walk in and take the Orca. You don't need to post a visible guard at the exit, but nobody is watching the exit at all.

Stupidity: It was pure stupidity for Riggs to bring Rika back at her residence after escaping the hit on Riggs. The villains know where Riggs' love interest lives and this nor the option to hide somewhere else or safer never occurs to him?

Stupidity: The lack of security at the château is not plausible. The Germans typically would have layers of protection around headquarters or other sensitive areas. In the movie, there are two middle aged guys guarding the road into the Château. After that there are no checkpoints, no patrols, and no controlled access points into the castle. It makes no sense that dozens of officers would be left vulnerable to an attack by French resistance fighters, let alone an Allied airborne assault.

Stupidity: When the parents knew Freddy was doing the killing then why didn't they watch him like a neighborhood watch so they could catch him trying it again, and thus avoid the legal technicality which threw out of the first case? It seems idiotic they broke the law to punish this lawbreaker.
Suggested correction: The parents believed Freddy would not face justice for his crimes. They were unwilling to allow him the opportunity to kill another child, and believing the justice system had failed them they took the law into their own hands. They completely got away with their vigilante justice. The only bad thing that happened was Freddy was brought back as a vengeful demon with superpowers. There is no way the parents could have known this would happen.
It is still a stupidity. Even if they wanted him to suffer, they would try to avoid legal problems at all costs. It is good that they wanted to prevent him from killing another child but they still shouldn't act so hastily.
Stupidity entries are not meant to be stupid acts by characters. They're for minor plot holes. Without in-film evidence why the acts would be a plot hole, there is no stupidity mistake. And assuming what characters would or would not do does not make a valid mistake (not to mention revenge killings do happen in real life and in movies a lot).
No, it's not. What else were they supposed to do when he was caught and set free? It's still not their fault what happened next.

Stupidity: Lecter fires the first bullet to alert the police that something is up, and the lift goes up, then comes down. Now in all this, only 6 or 7 go up the floor where Lecter was. Why aren't police sent in groups to investigate every floor? Lecter could have been anywhere, instead there are about 30 police huddled on the lobby floor.

Stupidity: In the scene with the water-jug puzzle, both Zeus Carver and John McClane initially suspect that the small carrying case contains a bomb. McClane goes ahead and opens the case, which confirms that it is a bomb (the electronic readout in the case even says: "I AM A BOMB. YOU HAVE JUST ARMED ME"). If they suspected it was a bomb in the first place, why didn't Carver and McClane immediately try to warn the dozens of pedestrians all around them to evacuate the area before McClane opened it? That would be a seasoned police officer's first instinct. Instead, McClane and Carver banter and bicker and never attempt to warn the public, even as the timer is ticking down.
Suggested correction: This carries over from the very first time McClane and Zeus talk to Simon on the phone (the "As I was going to St. Ives" scene). Simon tells the two not to run and McClane assures him they won't but that there are at least 100 people on the street, to which Simon responds "That's the point." McClane takes this to mean he can't just warn everyone or Simon will set the bomb off. They open the case because they don't know that doing so will arm the bomb. They wanted to know if there was a riddle or more instructions. Having the bomb be armed by being opened, complete with the pithy text "you have just armed me" was just a way for Simon to torment McClane. The bantering and bickering is of course, still pretty stupid but is consistent with how the characters behave for the entire movie.
Still, McClane's whole motivation in this movie is to save innocent people from death, which goes above and beyond his motivation in the first movie (which was to save his wife). What is the whole point of disarming the briefcase-bomb in the park if not to save the public? As stated in the original post, no seasoned and dedicated officer of the law would proceed without warning the public.
Except he was told specifically earlier not to do that. If he warned people of the bomb, it was implied that Simon would remotely detonate it. It can't be "stupid" of McClane to not warn people if he thinks doing so will get them killed. I agree that it is a trite movie cliche that a cop doesn't act like a cop would in the real world, but in the context of this film McClane's actions are consistent with the instructions Simon gives him.

Stupidity: A major effort is put in the future to develop the time portal, so they can recruit people from the past to help fight the war in the future. Yet they never seem to think to share anything with the past about the creatures and how to kill them or find out where they came from so the can help either prevent it from happening or help save the future before humanity is wiped out. Muri does recruit Dan for this purpose but it seems wasted to only use 1 person for this much more important goal.

Stupidity: Batman finds the Ice Princess on the edge of the roof, standing on the wall. If she's no longer bound, why didn't she just jump down onto the roof and negate the risk of falling to her death, which she did?

Stupidity: When Han tells Drydon Vos that he and Tobias will steal unrefined coaxium from the mines on Kessel, Vos initially says no, as Crimson Dawn's relationship with the Empire would be at risk. Han then explains that the Empire wouldn't know they were working for Crimson Dawn. Vos then agrees but insists his top lieutenant Qi'ra accompany them, even though she is a known associate of Crimson Dawn and literally has their symbol branded on her wrist.

Stupidity: Marta is shown to barf whenever she lies, and Blanc knows this. He should've asked her who did it right away. The entire plot of this movie is rendered unnecessary.
Suggested correction: That would only work if Blanc knew that Marta had knowledge of who killed Harland and if he came to the conclusion that Harland actually killed himself. Blanc doesn't know that Harland killed himself to protect Marta until Marta confesses. Also, this wouldn't have solved the "who done it" anyway, since Marta had no idea that Ransom switched the vials.

Stupidity: Mr, Freeze and Poison Ivy join together and plan to cover Gotham in freezing temperatures and plants, with none of them ever considering in the slightest that plants don't survive freezing temperatures, despite both of them being scientists.
Suggested correction: Poison Ivy made super-plants that could survive the new ice age they were going to create. As for the fate of normal plants, though this is only really clarified in the novelization (and original script), Poison Ivy's god complex has (pun intended) grown to where she no longer cares about individual or existing plants, just playing out her fantasies of being "Mother Nature."

Stupidity: Why does the team choose to enter the shimmer from Area X and then trek for miles to the lighthouse? They could travel by sea and stage an amphibious landing on the shore right at the foot of the lighthouse. Obviously this would make for a very short movie, but this choice still needs to be explained in the plot.
Suggested correction: I thought it was an obvious tactical choice to go by land. If the mysterious shimmer radiates in all directions for miles, as it seems to in the movie, then it would also radiate for miles out to sea. A recon team is going to have a lot more options to deal with any "weirdness" on the ground rather than on a boat or in the water. (Also, the book "Annihilation" on which the movie is based makes it clear that there are some really big, nasty things swimming around in the water!).

Stupidity: When the teens are about dump Ben Willis off the pier, he regains consciousness and snatches Helen's crown. Despite knowing he's alive with strength to spare, they nonetheless drop him in the water and continually refer to him as "dead."