Stupidity: Dirk squeezed a long stream of lighter fluid onto the pile of Mario's clothes, then saw a necklace, which he removed (and potentially got lighter fluid on his hand while doing so). Instead of tossing a match from a safe (r) distance, Dirk crouched next to the saturated clothes and held a match near the bottom of the pile, risking burning himself. (00:06:40 - 00:07:21)
Stupidity: Thor looked for (and found) "weapons" in the back of his parents' closet, but didn't think of getting knives from the kitchen. Also, when Claude was in the house, Thor put the paintball gun in Max's backpack in case someone messed with them when going for the drone but had not thought of using it before Claude arrived.
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 Joan is in hell and is confronted by the overlord, she attempts to shoot him with the BFG-9000, so the overlord uses his powers to telekinetically blast Joan away and disarm her. A minute later, Joan picks up the BFG-9000 again, but the overlord never considers using its powers to blast Joan away from him again, which results in him getting killed.
Stupidity: Despite the fact that the villains know exactly where Brogan is for the better part of the movie thanks to a tracer, and that they display constantly that they are able and willing to hit with bold military operations even to the point of hitting an urban area overruling law enforcement (apparently Clay has authority to do that too), Brogan is able to get undisturbed back in the US through his friend's plane. Considering he was officially marked as a rogue agent and killed 8 DIA operatives, it's hard to see how Baron's plane could ever land on American soil after a long intercontinental flight.
Stupidity: The marble somehow got under Don's skin at the bottom of his leg and was moving up the length of his body. Instead of heading off the marble in order to intercept and stop it from continuing up his leg, Don got a knife/box cutter and jabbed it into his skin near the bottom of his leg and trailed the marble, causing a long gash that served no purpose (other than creating a lot of blood and making a gory scene). The marble eventually exited his body via his eye. (01:04:40)
Stupidity: The movie takes creative liberties with the real story; it's understandable, for instance, that it would show Paige being directly on NXT rather than part of the Florida Championship Wrestling promotion first, and that she is the only real character from NXT depicted in the movie. However, the movie chooses also to omit the fact that Paige was NXT Champion when she faced AJ Lee. Not just that, but it alters entirely the dynamic of the actual match; she does not manage to utter a single word because of stage fright, something that movie-wise she seems to have never managed to overcome. Given the changes, the movie asks us to believe that WWE would make a champion out of a complete rookie who is a deer in the headlights in front of a crowd that ignores her and hasn't found her personality yet - she does so only after she wins. That doesn't make a lot of sense even by the movie's own logic.
Stupidity: The kidnappers steal a silver Citroen van and take it to a junkyard to switch the plates. They steal plates off an older green color Asian type sedan and place them on the van. If the cops run the plates as they normally do random checks as they drive, those plates will not match that vehicle. They should have found the same make and color of Citroen van they stole and swapped plates for plates, the chances of the owner noticing are small. Now if the plates get run they match that vehicle. (00:00:38 - 00:01:18)