Stupidity: The commando mission to save Chewbacca starts gunning down a few Stormtroopers in the hangar. The heroes then go on leaving the troopers lying down on the floor in front of the ship, in plain view. They don't hide them nor ask the droids (who have enough strength and tools to pull them in) to, in fact they tell them to stay put. No wonder they are found out later (after a ridiculously long amount of time).
Suggested correction: Hiding the bodies would have been a waste of time, anyone who came to the hangar would immediately notice that the guards stationed there were missing and there was now a strange ship parked there.
The droids have all the time in the world, and people just passing by are "more immediately" bound to notice corpses in the middle of a hangar rather than possibly maybe question the fact that you don't see guards in that part of the hangar or investigate the ship - which could approach without anyone taking exception by appearance alone. At least remove the bodies directly in front of the damn ship!
Why would they be more likely to notice dead guards than no guards?
Anyone passing by might well thing the patrols were just out of sync, or a shift change. Sure they might investigate further, but they might not bother. Whereas a couple of dead bodies? Immediate red alert. Worth taking 30 seconds to hide them, surely.
Perhaps, but then it's made irrelevant 1 minute later as Finn and Poe run down a hallway blasting about a dozen stormtroopers.
For that matter, 1 SECOND later they kill stormtroopers in the far part of the hangar. They are killing people all over the ship during their mission and it's not like they hide every single one of them, but they leave two bodies *exactly* in front of their ship (and telling the droids to stay put). You can even see later that there is a stormtrooper with his weapon pointed exactly where those two corpses are, with the 'smart' commanding officer asking "whose ship is this?" at the sight of that. Maybe I am spoiled by a trope here, but it's the first time that I see someone in an action movie leaving corpses right in front of their only escape route/vehicle, that's so counterintuitive. (Did they even have an escape plan, actually? I don't like hypotheticals, but gee, if only she did the Jedi mind trick thing to those 2 guards who came over to inspect the ship instead of doing it later. But I digress).
Stupidity: You'd think that Jezzie would have been a little smarter as a secret service agent. You know, like once they acquire Megan, to delete all the incriminating evidence sitting back on an unattended computer. Aside from the fact she also used quite a stupid password, a single password isn't very secure at all. And then the content, displayed instantly when you get in, might as well say things like "hey look, we know what the kidnapper looks like" and "wow, here's the boat he's in too" and "wow, a cabin for sale. Why don't we go hang out there with all the evidence." Come on....they might as well have left a trail of breadcrumbs, because they sure were asking to get caught.
Stupidity: If Jordan was inside the cake and the cake was right there in the room when the takeover began how did the bad guys forget she was still inside?
Stupidity: When the Keymaker is closing the door to the room that leads to the Source, he stands in the doorway resulting in the multiple Agent Smiths gunning him down. He could have easily closed the door without standing in the doorway and consequently would have lived.
Suggested correction: Who says the door was bullet proof and the Keymaker couldn't have been shot through the door?
The point of the stupidity is that he shouldn't have been in the doorway at all, even if the door wasn't bulletproof, there was no need for him to even stand behind the closed door. He could have pushed the door closed from the side.
It seems to be a heavy door, he simply couldn't close it with just his arm, thus he had to move his body forwards in order to close it. In that brief moment he got shot before the door closed. He could have for example kicked the door shut but he simply didn't think of that at that moment, also not knowing the Smiths were about to fire a volley of bullets at them.
Stupidity: When Christine is told that to remove the curse, all she had to do was give an envelope with the button inside to somebody else and that individual would go to hell. She decides to go to the cemetery where Ganush is buried and places an envelope into her mouth. Had Christine actually bothered to check inside the envelope first to see if the button was inside, she would never have gone to hell.
Stupidity: When Colonel Hardy is about to crash the ship he's flying into a building, Faora sees it and she has more then enough time to leave the ship and get to safety, but she does nothing and just stands there.
Stupidity: The bad guys should have just shot Paul and his backup during the standoff rather than risking another impediment.
Stupidity: In the first action scene where James Franco's body becomes mortally engulfed in flames in his cryopod, when they are using the jaws-of-life-hatch-removing tool to manually free him, there are two very strong men struggling with all their might to pull down on the levers to pop the lid off. A) If you watch closely, one of the guys is only using one hand to pull down on the lever. Hardly a serious effort to crank the thing open. B) Meanwhile, there are three other men present who, rather than jumping in with the other two guys trying desperately to pull those levers down, are instead ridiculously engaged in holding Franco's hysterical girlfriend back from the now-flaming pod. (00:10:00)
Stupidity: When Ruth catches Chuck fishing for turds in their toilet, he yells at her and asks for privacy and then slams the bathroom door shut. He should have closed the bathroom door in the first place if he didn't want anybody to see what he was doing. It's not like anybody would think he was weird for going into the bathroom and immediately closing the door.
Stupidity: Bori Khan is a skilled archer and a man without honor. He's not fighting fair, and cares just to win, as established and explicitly said. He shoots an arrow at Mulan, the Witch gets in the arrow's way sacrificing herself to protect her...and for no reason whatsoever he does not shoot anymore, giving the chance for the two girls to share their very special dramatic moment together, but creating a colossal plot contrivance. It is a know movie cliche for the fight to 'pause' around the main character, but here we have a sniper who desists completely (he won't shoot anymore) for absolutely no reason. (01:29:00)
Stupidity: Shriek is being taken to a new facility for superbeings, after a medical exam established that her sonic powers that she has been using since she was a kid are too strong to keep her at the correction house. So "naturally" for this transport she is not gagged, sedated, not even bound, and there's just one guy with her, not even wearing earplugs. It couldn't possibly be any more comically unsafe.
Stupidity: At the beginning, young Indy knocks out the driver of the car, pulls him out, and just leaves him on the ground by the car while entering the car. Neither the knockout nor the unconscious driver lying around are noticed by any Germans in the vicinity. Not even by the soldier who opens the car door and the officer who gets into the car, both of whom immediately appear after Indy has gotten into the car. (00:06:00)
Stupidity: After stealing the taxi, Cassandra removes the license plate, and yet the taxi's identification number is located in bold plain sight on the doors and roof light.
Stupidity: There is no security team on earth that would allow a major pop star to walk around in the hallways of an arena without being by her side at all times, not to mention allowing her to be alone in a room with a stranger she just met that night.
Stupidity: Granted, Coffee is suffering from "high-pressure nervous syndrome," but if you're a Navy SEAL, wouldn't you notice whether or not your pistol has a magazine in it? Monk pulls the clip out of his jacket and starts knocking rounds out of it for the rig crew's benefit; the same dramatic effect could have been achieved with a handful of cartridges he could let slip through his fingers. You could argue that Monk didn't have enough time to unload the gun and replace the magazine, but in that case, I think the scene where Monk briefly had the gun should have been a bit longer. (Even had the empty magazine been IN the gun, Coffee still might notice the difference in weight, but that would be easier to suspend your disbelief for.) (01:43:53)
Stupidity: Jill wasn't thinking too clearly when she plans her story. She only wiped the fingerprints off the gun but they would be all over the tape on Trevor's body. Then she wipes off the knife yet touches it again to slide it across the floor. She was thinking that Trevor and Charlie were going to be thought of as the killers but their fingerprints weren't on either of the weapons.
Stupidity: During one of the test drives, the hook that Hiccup uses to fasten himself to Toothless gets bent, so he takes Toothless to the blacksmith to cut the line. There are two ways he could have easily avoided this: He could just unhook the saddle, take that to the blacksmith and cut himself loose, or he could just untie the leather strap. What he does here is needlessly risky and just there for his awkward conversation with Astrid.
Stupidity: When Gaz tries to steal a jacket and Dave, who works as security, catches him in quite a dramatic manner they are seen by other employees. Dave lets Gaz go because he is a friend. But the next day both stroll together through the shop as if nothing had happened, with no enquiries or follow-up from the other employees. (00:59:30)
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."