Stupidity: When Steve Martin reaches the beach with the wheelchair, he tips it over, giving the illusion that he fell out of it. However, with where he starts crawling on the beach, it's tipped the wrong way. If it was that way, he would've been on the other side of it. A clever con-artist should know better.
Stupidity: Robin uses the high pressure water from the pump to neutralize the bear next to Batman (which is like 10 meters away from him and still the water jet is so strong that it pushes the 1000 pounds bear away and flips it on its back,), but does not use it to push away the other bear that is literally breathing on his face centimeters away from him. He has all the space and time to do that (especially after Batman's intervention). (00:50:30)
Stupidity: It was very idiotic of Turner, who is an experienced serial killer, to not only knock out and take Julie prisoner, but to attack Kale as well, considering the recent circumstances. The police and Julie didn't believe Kale, and Turner suddenly goes on a rampage? He took a huge risk when he attacked Kale and could have very easily blown his cover.
Stupidity: Angela ran over to her neighbor Mr. Charlie when she heard him come home. Angela was complaining that his son and friends make too much noise, do whatever the want, are bringing property values down, act wild/crazy, draw attention to everybody, and she doesn't want the police coming. These may be legitimate complaints, but the way Angela expressed them would bring down property values! Not only was she yelling in the street, she used "m-f-ing" several times, as well as other select words. (00:02:35 - 00:03:07)
Stupidity: The Chief Inspector wants the video cassette back because it shows him committing murder. Yet he spends the entire movie shooting and killing people in public trying to get Johnny and the cassette.
Stupidity: Johnny bleaches and cuts Ponyboy's hair and cuts and washes his own, thinking that would make them not fit the pictures of them. They look the same just with blonde hair and not greasy hair.
Suggested correction: I think you are right to a certain extent, but not necessarily when things are put in perspective. For example, they were "Greasers" and a certain image was attached to this status. Something like washing their hair would make them less noticeable among "Soc's" and other non-Greaser statuses. Anyone looking for them would not automatically assume they washed their hair or had the time to get hair cuts and bleaching while "on the lam." If an APB went out, it would contain their usual appearances.
Stupidity: When Alice opens the door for the dumbwaiter, how did she not see the bottom of the elevator was removed when she was looking right at it? She even realised it was missing as she was getting in, but she still let go and fell to the basement.
Stupidity: The building is supposed to be without power - at all since the generator has been destroyed - and life support machines are not powered up, but the 3D printers in every room are powered up - so that the good guy can squish the bad guy's head in it, and the elevators, so that the good guys can escape. What sort of hospital has its electric grid rigged in a way that the elevators keep working but critical surgical equipment goes dead the moment the power fails? (01:12:00)
Stupidity: In the flashback about the way the victim was poisoned, it would seem that the murderer straight out went to a waitress and handed them a single chalice of poisoned champagne, ordering the waitress to give that exact glass to the victim. That's just a little bit absurd; if it's a flashback based on a testimony, the case should have been solved in 0.1 minutes once the waitress says that that very well known person asked them to bring a glass to the victim - it's a request highly unusual and that would be easily remembered. If it's just some wild guess of the detective, that's a mighty strange way to imagine how things went, rather than just the killer slipping venom in the victim's glass when they were not looking. (01:04:00)
Stupidity: Instead of breaking into Gordo's house, covering all the furniture in one room with sheets/thin blankets, and waiting for Gordo to return home in order to kill him via a "dramatic re-enactment" (in an adjacent room which was not shown to the audience), Bill could have taken Gordo anywhere to avoid getting caught or calling the police on himself. Had Bill taken Gordo to his already-"wrapped" motel room, he had enough injuries after the fight to claim self-defense against an intruder. (01:43:20)
Stupidity: Why would the tow driver go around Deacon's truck in the one-way dead-end parking lot to pick it up from the front? He'd have to back it up on the hook, and Deacon's truck would be in Park, making it impossible. There's a reason tow trucks hook up vehicles by the drive axle ends. (00:08:40)
Stupidity: I seriously doubt that any Mexican Mafia cartel operating here in the U.S. would waste their time eliminating two simple patrol officers. There's nothing to gain by doing so, and it would bring a war between themselves and the police, which in return would bring hundreds of arrests of key members, drug busts, raids of their operations within Southern Cali, etc. They wouldn't risk their business taking millions of loss of revenue all to kill two patrol beat cops.
Stupidity: A load of cars is in the tunnel with the overhead lights off, and none of them has thought to put their own lights on (as covered already). Then John gets out of the car, only for one car to suddenly flick its lights on and nearly run him over, having been driving at full speed in the total darkness, apparently.
Stupidity: In the bar scene, Jack gets into a fight with a guy he busted a few years back, then Reggie turns to the bartender and asks for a gun. The bartender hardly hesitates and hands it over. There is just simply no scenario where a bartender would hand a loaded gun to a patron they had just met.
Stupidity: A movie always needs extra conflict, but Julie's reasoning for walking out on Marcus and Mike is one of the dumbest. "If his wife can find us, I'm a LOT better off on my own." What sort of logic is that? She's the wife of his best friend. Of course she knows where he lives. (01:32:45)
Stupidity: Early in the movie, AMMO and its crew show remarkable prudence in their approach to the drug deal, and a point is made about them following procedure, planning accurately using technology and trying to minimize collateral damage. The sting at the club goes against all of that. At the end of the day, it just consisted of getting close to the target and pulling guns on him in the middle of a crowd of civilians, the exits of the place (the front door even) completely unguarded.
Stupidity: There is a scene in which the phone rings back at the house and Andy goes to answer it. None of the henchman respond immediately, but instead WAIT for him to almost answer the phone before becoming making a move. You would think they would yell at him to not answer it or have one of them rush to guard the phone the moment it rings. Obviously the entire scene was done this way for the sole purpose of suspense.
Stupidity: When she leaves him at home with a sandwich she says people will come check on him. When she gets home and he's not there, she doesn't go and ask those people where he is.