Stupidity: Why did the bad guys even go for Xander as he was snowboarding down the mountainside? First of all, it was impossible for them to even get to him as the mountainside had several cliffs. Secondly, why did so many go? Wouldn't it be clever to have as few as possible leave in case his snowboarding was simply to draw attention away from an ambush? They knew he was an agent by now and should know he could have gotten reinforcements. Thirdly, they could just have simply waited for him to get to them.
Stupidity: They make a big deal about how they've got the bare minimum of Pym particles left as Hank has been snapped away, but it never occurs to them to use their supply to jump back to a very safe time when Hank was around with a vast supply of them. They could bring them to their time and then have no end of attempts to get the stones without being on such a knife-edge.
Suggested correction: The problem is that they need to steal particles, and if they fail doing that, everything fails. They never thought of doing it that way because of that. Only when they failed in the past did they have to risk that, with again the possibility of failing. They couldn't take the risk to have their only chance of reversing what Thanos did fail because they want to be leisurely about it, ironically. They could do it in one go, that was the best bet and lowest in risk.
Stupidity: Alex, a contract killer, went to the hospital to kill a patient. After parking in the hospital garage, Alex put his car keys under the sun visor, risking the possibility that his car could be stolen. When Alex returned to his vehicle, the keys were not there. A professional or expert assassin should take precautions to assure his getaway car will be there and keep his keys on him. (00:01:45 - 00:04:30)
Stupidity: One of the actors microwaves bullets and then loads one into a weapon. Only problem: she/he (I did not pay attention) puts the round the wrong way around into the magazine. Then the person loads the magazine with the one round visible in the wrong direction into the weapon. I would say that this should not be working. (04:25:00)
Stupidity: The whole movie happens for unbelievably convoluted causes. Despite their friendship and the simple fact that he still runs an occult shop (showing that he's not exactly insensitive to the past), Ray in years never spent a single moment to check on Egon's whereabouts, which he knew, or listen to him. The city has Shandor's name all over and any cursory investigation would have unveiled the connection. Assuming of course that Egon turned into such a lunatic he couldn't do the namedropping himself.
Stupidity: Suspension of disbelief is fine for a movie like this, but even as a child I found unbelievably silly the fact that the Ghostbusters use a Nintendo controller to move the Statue of Liberty. The concept is never set up and never is shown properly; all the movie showed and told us was that items possessed by the slime dance wildly to the beat of music. There's no logical (as in, movie internal logic) passage between that and "so we fire up some beats and it won't start dancing to it, but just calmly move according to our inputs on a joystick."
Stupidity: After so many failed attempts to open the large sea doors, why didn't the apes first breach the facility by climbing to the top of the cliff and simply enter through the existing rusted out exhaust vents where they escaped the rushing water?
Stupidity: Considering Rocky keeps hitting Drago after the bell sounds to end the round in their main event fight shouldn't he be disqualified?
Suggested correction: This is up to the discretion of the ref. If he deems the strikes to not be particularly egregious he can let the fight continue. Even if they are deemed illegal strikes, that doesn't mean that Rocky will be automatically disqualified. The ref can dock a point from Rocky instead, which he very well might have done at some point which we never see. Since Rocky wins by knockout having a point docked doesn't matter.
Stupidity: There was no particular reason for Nuclear Man to take Lacy into the space in the first place.
Stupidity: Arishem's plan with the Deviants hardly makes any sense; he sent out biological beasts that he can't control, to kill off the natural predators of every planet. Forgetting the fact that obviously it didn't work (but the movie does not say that) because Earth has always had predators, that's a terrible plan to begin with, since any ecosystem needs predators or the other animals will grow uncontrollably.
Stupidity: After the fight in the woods Bond walks back a long way, instead of driving the Toyota he had left in the forest in full working order.
Suggested correction: The Toyota has had a major chase over very rough terrain, it may no longer be operable.
It was operating fine when they stopped it in the middle of the forest.
Stupidity: When Cougar (and later, Maverick and Goose) report to Stinger's office at the beginning of the film, a photo of an F-5 in flight (or possibly a T-38) appears on the wall beside his desk. However, the F-5s that appear in this movie are standing in as MiGs. Of all the aircraft photos the set designer could have selected for this scene, it seems strange to use one of an "enemy" aircraft.
Stupidity: Given his speed, surely Superman could've stopped both missiles with no problem.
Stupidity: Why would 006 put Bond in a self destructing helicopter instead of just shooting him? Being Bond's old partner, he of all people should know how good of an escape artist Bond is.
Stupidity: When they are preparing for a German assault towards the end of the movie, Miller explains to them the concept of the sticky bomb and adds, "If you have a better idea of knocking the treads off a tank I'd like to hear it." Um... The bazooka? They had eight rounds for it, and it could have easily been used to disable the treads. And the men wouldn't blow themselves up with it. While it couldn't destroy a tank by penetrating the armour, it's certainly strong enough to disable the tracks.
Suggested correction: Allied forces familiar with the Panzer VI "Tiger", a 60-ton Main Battle Tank during the war knew that the armor is very tough and, even with support fire from a friendly tank, the odds of destroying a Tiger tank with a bazooka like Horvath's are pretty small. From the infantry perspective, techniques that were developed and employed in order to combat heavy Tiger tanks focused mainly on disabling the tank rather than destroying it. Anti-tank weapons of the era, such as the bazooka, were ineffective against most areas of the Tiger's armor, so specific weak points in the design were the focus. Hitting the Tiger in the tracks, suspension, engine compartment, observation slits, and in the joint between the main body and turret were some of the common weak points. Tiger tanks could only be destroyed head-on or from the sides by land mines, or direct hits by heavy artillery shells, or bombs dropped from aircraft. In the film, the first Tiger is disabled by taking out the tracks with "sticky bombs" followed by grenades thrown in the turret hatch. When Horvath fires at the second Tiger, both shots are placed on the joint between the body and the turret, the idea most likely being to hinder or incapacitate the turret's ability to swivel left or right. As the war went on, the Allies developed better strategies for disabling Tigers. One example involved British Cromwell or US Sherman tanks trying to "flank" a Tiger by working in squadrons or columns. One or more tanks would act as a diversion to keep the Tiger's crew focused in front of it while another tank would maneuver behind the Tiger and hit it in the rear section where its armor was the weakest.
Stupidity: The bad guy who spies on Bosley is visible from the very beginning of the scene, when Elena is not even inside the cafe yet. The cafe does not have many customers and the bad guy is using a loud vintage typewriter with a big mirror mounted on top (!). The Angels are portrayed as being super smart and their setup is so careful, but somehow they managed to miss something amazingly obvious. Conversely, nobody would have ever paid attention to a laptop or any silent, modern-age device perhaps with a camera or something similar, so the bad guy chose the most blatantly conspicuous accoutrement for his spying job. Try showing up to a cafe punching the keys of a big clunky typewriter and literally everyone will be looking at you. (00:18:25)
Stupidity: When the rebel leader talks to Rick Flag guaranteeing her help, she mentions that she will help to find "this Gaius Grieves", speaking as if it was someone unknown to her. He's been around the island (going to bars and surely not being reclusive) for 30 years; it's pretty difficult to think it would not be one of the most known people on the island, given his role, unique appearance and the small community.
Stupidity: They could've used the flying chopper thingy to kill off the armed guys when rescuing the kids off the train carriages. That way they could have made sure they got every single kid rather than rushing to just take the one containing Minho (which they messed up).