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: All that chaos going on at the end of the movie. Gun shots. Screaming. Blowing up police cars. Yet not one neighbor comes out to see what's going on.
Suggested correction: Gunshots and explosions going off at a neighbor's house isn't going to make me go and investigate. It's going to make me call the police and hide in my own house.
Stupidity: Vincent's choice to cut the power to the building that Annie is in does nothing but waste enough time for Max to save Annie. It would have been easier just to go up to kill her and he probably would have gotten away from the police if he did so.
Suggested correction: It also slows Annie and Max down by forcing them to walk in the dark, and also, at this point, Vincent is really torn up from the crash, and the mere sight of him is going to make Annie very suspicious or even afraid, unless the power out (which for all she knows is just from the building) gives him a plausible reason for being so mauled.
Stupidity: Captain Poison has a fairly good idea of where Solomon buried the diamond. We know this since when he leads the captured Solomon to the spot, there are already several holes dug looking for it. Despite knowing roughly where the diamond is - down to a relatively small area - he makes no serious effort to excavate the ground, instead contenting himself with a handful of incredibly shallow holes.
Stupidity: (SPOILERS) Despite knowing that Rowena killed the last person who was blackmailing her, Miles tries to use her secret to blackmail her into sleeping with him. Did he really believe that she wouldn't react with such drastic measures like she did before?
Stupidity: When Amy tries to use the security cameras at Desi's house to make it look like he raped her, wouldn't the cops be curious as to why there was just one little scene - and not 30 days worth of footage? Wouldn't they question what happened to the rest of the footage (showing her being looked after by Desi and living comfortably), and why that little bit showing her crawling on the ground was left undeleted. Also she tied lace around her hands. Anyone could break material like that if they tried hard enough. Why would Desi risk that?
Stupidity: In an empty sewage tunnel, after Elsa saves Ethan, there just happens to be a defibrillator.
Stupidity: Why didn't they take out the crushed hand guy while the creature was fumbling inside the glove? Plenty of time to do it. Why did no one use a knife to stab the creature?
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).
Stupidity: After one of the policemen decides to jump over the railing and right into the angry mob (!), Arthur just easily sneaks by ducking under it and takes a nice stroll that will lead him through an unlocked door. Nobody in the mob he is part of decides to do the same, and you can also see that one of the policemen is turned towards him, but does not even yell at him or move. And of course, with the theater packed with the Gotham elite basically under siege by a mob and guarded by the police, the door is unlocked and unchecked. Why not. (01:02:55)
Suggested correction: The point is they were all too distracted by the tussle to notice Arthur ducking behind the barrier. No cop sees him. The angry mob is controlled by the barrier and not all that large so they haven't taken extra precautions to keep the mob at bay, yet. The door Arthur gets in is probably a fire escape and can't be locked for safety reasons.
I think that with an angry mob worth putting barriers and a big police dispatch, they'd tend to lock the door that is like a 20 feet of walk in a straight line. I mean, they have barriers in front of the stairs, but at the base of the stairs there's an unguarded, unprotected, unlocked door. It's just funny. Not even something in the back or around the corner, no; literally one step to the right of the blockade.
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: While Mr. Butler was upstairs taking a shower, Lucas goes into his house, kills his wife, and takes the baby to the school (into Mr. Butler's classroom). Lucas wanted to take away Mr. Butler's family, so all he needed to do was also kill the baby at the house (or leave the dead baby outside on the porch for Mr. Butler to panic while searching). Lucas could have left the house without getting caught for committing a double murder; instead, he keeps the baby alive and assumes Mr. Butler will know he took the baby to his classroom. (01:17:53)
Stupidity: Liv and her five friends went to Willy's to set it on fire, but Liv insisted they first go inside to get the Janitor out. All were aware of the situation and danger related to the mass murderer and the animatronics, but Bobby and Kathy went into another room to "hook up." Kathy recognized the room as the one where the killers committed suicide and later saw movement, but she continued having sex with Bobby until he was attacked and killed. (00:38:48 - 00:42:02)
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: The protagonist with her kid stops a car with two guys, in the middle of the night in an isolated country road. Both the adult and the kid scream that a dangerous maniac is chasing them. So naturally, the two guys (who do believe them, it's not that they are being dismissive) offer them some hot coffee, and they drink it right there in the middle of the street, not dialling for help, getting in the car to drive away or anything, because that's what normal people do when you tell them a serial killer is nearby; stop for a hot cuppa.
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 fact that Nolte even gives in to Eddie's demands is ridiculous. Why not just interview him in prison, ask him where to look for certain people, etc, and if it's a dead end, report back and ask for further tips, etc. They had zero problem going to prison and asking Kirkland Smith in the sequel.
Suggested correction: He refused to tell him anything unless Kates takes him out of prison.
Stupidity: It is pretty silly for Martin Lawrence to go undercover as a police officer when it would make way more sense to go undercover as a janitor/custodian since his main goal is to gain access to the vent. A janitor would be a way less conspicuous disguise than a detective and slipping through a backdoor entrance disguised as a janitor should not be all that complicated for someone as savvy as Myles. But of course this would make a far less entertaining film.