Stupidity: Felix and the DEA capture Sanchez, a very powerful drug lord, in a very public way, have the wedding...then everyone just goes home. No concept of extra security or concern about his minions getting revenge. So of course they can then just wander into his house with no problems whatsoever to capture him and murder his wife. Bond's clearly concerned when he learns Sanchez has escaped, but he must have realised there'd be plenty of goons still around before that point.
Stupidity: When the flying snowmobiles attack, Bond tells Elektra to go into the gully, and he'll lead them into the trees...completely ignoring the fact that these bad guys are here to kill her, so why would they follow him instead? Of course they all do. Either a plot contrivance or a blatant set up, which he doesn't remotely consider.
Stupidity: Jimmy and his friends aren't allowed by their parents to go to the opening of Retroland because it is a school night. What kind of amusement has its grand opening on a school night? It would make more sense commercially to open on a Friday or Saturday night.
Stupidity: So if Harley Quinn drove the truck to blow up the plant, wouldn't she have had to drive through all the cop cars at the bar murder scene? We know it was the same street because the cop gives the necklace to the detective. (00:10:58)
Stupidity: At the end of the plane chase Bond fails to finish off Hinx. Regardless whether he thinks he's dead or not, with a licence to kill he should have made sure.
Stupidity: Jake uses several Loops and travels all over the world in order to get back on the boat at the end of the film. This was completely unnecessary as only the final Loop in 1942, which was available to him in 2016, was the one he needed to enter despite the fact that its nature should have prevented him from reaching 1943 anyway.
Stupidity: When Jonathan is chasing the truck to try and save Sarah, he could have removed his heavy backpack and run faster...but instead just leaves it on. No wonder he wasn't fast enough.
Stupidity: When the plane begins crashing, Kayla tells Claire that she is sitting in an ejector seat. She also mentions that there are no parachutes because she "wasn't expecting company." If Kayla was expecting to be alone in a crash scenario, what use would installing the ejector seat in one of the passenger seats have been? She would have to move from the pilot seat to the passenger seat while the plan is crashing. Surely it would've been easier to install the ejector seat in the pilot seat.
Stupidity: Even though Hermione reminds them that they must not be seen after freeing Buckbeak, they fly toward the castle, whooping and cheering because they're flying. Then, they land in the courtyard of the castle, have a conversation, and then Sirius flies off with Buckbeak. Not the behavior of trying to remain unseen and unheard.
Stupidity: Goku defeats the henchwoman of Piccolo in the lava pit quite easily; she looks human. He is quite content to just push her off-camera with a smack, and nobody cares about trying to talk to her, figure out Piccolo's location and plan, or anything like that. Everyone just forgets about her, and it turns out she even eavesdrops on the lot before leaving. Someone would so casual about meeting and defeating the mysterious enemy only in a movie where you know the script already. (00:46:40)
Stupidity: The X-Men depart for space on a vehicle not designed for space, for an incredibly dangerous mission they know nothing about (and none of them can survive in space at that point), but don't suit up for it in the slightest - and with Nightcrawler and Quicksilver's powers as they are shown later, it'd be easy to do it without wasting time. Not only that, but Xavier communicates with NASA to get the briefing only after the X-Men have already departed.
Stupidity: The protagonist is wearing normal boots atop a spacesuit while being on a moon mission. (01:37:11)
Stupidity: The bad guy's henchman has a plan to stop XXX from reaching the wagon with the President. He hides in the kitchen compartment, which is in a separate area that XXX has to decide to look up and get inside of for no reason (guess that looking at Ice Cube he guessed he'd be going for a snack at some point), leaves his automatic weapon on the floor and just waits there in a ceiling compartment with a knife. If he just shot him through the wall or the door, I guess it would have been too easy. (01:26:20)
Stupidity: Why would Stanley say the shoes fell out of the sky? It happened under a bridge. Any normal person would instantly realise someone threw them off the bridge.
Suggested correction: It's an idiom/expression. When something turns up out of nowhere, we say "it came/fell from the sky." In fact, Mr. Sir says this to Stanley when he finds Stanley with his empty bag of sunflower seeds, "Where did this come from? Did it fall from the sky?" Obviously a sarcastic way of saying, "it didn't get there by itself, someone put it there." So the shoes obviously fell from the bridge and Stanley knows this because Zero refers to the bridge later in the movie.
Stupidity: Bond has been shot at and hunted down by armed men and dogs. He must conclude his life is in danger, and yet after Bond despatches the armed man in the creek who is carrying a British Sten submachine gun, he fails to pickup the weapon which has far superior firepower to his small calibre hand gun. Had he done, so he may well have saved Quarrel and avoided capture.
Stupidity: Kora and Gunnar arrive at the town to find the rebel Bloodaxes via a contact of Gunnar's. They literally see this contact being hauled out of a bar by bounty hunters who work for the Imperium...and then walk straight into the same bar and start openly talking about needing to find the rebels right in front of the bartender and other patrons, who for all they know are all Imperium-aligned.
Stupidity: When Winslow sees Tarek getting eaten by one of the monsters, he runs up to the monster and attempts to tackle him. Apparently, he just forgot that he was holding a machine gun and could have easily just shot the monster instead of trying to stop him by hand.