Stupidity: After the Defranco "assassination" Rollie learns he is a target and survives two attempts on his life. But instead of leaving town or finding somewhere else to hide for the night, he spends the night in his own apartment (even though he was well aware the killers knew where he lived). As a result, his girlfriend is killed and he barely escapes alive.
Stupidity: Noah chases one suspect while Leslie chases the other two. Noah eventually pulls out his gun and says, "Stop, police!" Leslie doesn't even try to draw her weapon until she hears sounds from the nearby brushes - but she barely has her hand on the holster when she turns around and gets punched in the face. Leslie is knocked over and the other man she was chasing repeatedly hits her in the face, quite hard. Her injuries could have been avoided simply by having her gun ready to aim and use. (01:04:48)
Stupidity: The protagonist knocks at every door, humiliates himself, losing any hope of getting his dream job, jumps through all sorts of hoops to get a court order to save Crawford's wife, but somehow, once he gets it, he has to drive through LA and physically get to the hospital room where euthanasia will be performed, because he couldn't be bothered to phone the hospital to tell them about the court order or talk to someone in the lobby.
Stupidity: When Poirot's team attacks the Germans, they do it through the cover of gas they release. The Germans are having a good time chatting and not taking the situation seriously when there's a big cloud of noxious gas advancing towards them. Despite Poirot's oh-so-clever plan, they should by all means know that something is coming their way, but they get caught entirely with their pants down.
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)
Stupidity: Soon after the new art therapy instructor Anna arrived for her first day at the mental hospital, Leena - the most dangerous patient - was not in her room and nobody could find her. The hospital went into lock down and the doctor took Anna to a room. Without first looking in the room, the doctor said, "Do not leave this room. Don't worry, you will be safe here and we'll come back after we found her" and then locked Anna inside the room - with Leena. (00:03:36 - 00:04:41)
Stupidity: Molly was being hunted and didn't know if she could trust Rayburn when he encountered her. Rayburn told Molly that he wanted to help, wouldn't hurt her, put a blanket around her, and even carried her in the woods for some distance. When he put her on the ground (along with his backpack and rifle) to go find the rope to open the pitfall doors and had his back turned, Molly got out from under the blanket and hid nearby. Rayburn quickly found Molly, and Molly made a lame attempt at attacking him with some kind of club. The next day when Rayburn and Molly were in Rayburn's house and her hunter showed up and attacked Rayburn, Molly grabbed Rayburn's rifle and fired several shots at the hunter. Molly obviously knew how to use a rifle, so it was asinine for her to have hidden from Rayburn the previously night without taking his rifle (or the blanket). (00:36:22)
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: When Joaquin was running from Cornell, he turned into an alley between buildings. He was to the left (of the screen), which was unobstructed, but ran to the right, so he could jump over boxes. Cornell could have also stayed to the left, but ran far enough to the right where he could kick the boxes out of his way. Easily avoiding the boxes would have been faster. (00:11:37)
Stupidity: After Casi changed the tracker on the Navigator, he was sneaking between vehicles to get out of the tow pound. The Whale came and stood in front of the two vehicles Casi was between. Casi stood up and, instead of turning around and running away, rushed TOWARD The Whale in an attempt to get past him. The Whale, much bigger, threw Casi against a vehicle and then onto the garage floor. (01:03:34).
Stupidity: One of the major reveals and plot twists of the movie lies in the fact that a certain character is an accomplice of the medium. The reveal, though, does not explain at all how said individual managed to fool Poirot; the trick briefly shown involves a simple rope pull to open a door. Poirot was looking exactly for that kind of trick, paces around the room constantly on maximum alert, and examines the door itself later. Likewise, it does not explain where and how they could hide the stuffed animal.
Stupidity: In the original novel, the attempt on Mrs. Doyle at the temples was made rolling a boulder off a cliff. In this adaptation, the culprit is said to 'dislodge' a large stone from the temple; you can however see that the stone is already dislodged and sticks out from its place on the pillar, and he had no way to know that the Doyles would be in that particular spot, making this attempt to Linnet's life rather nonsensical (requiring also herculean strength, no pun intended). (00:47:40 - 01:39:30)
Stupidity: Catherine, wearing a dress and coat, was outside in the snow chopping firewood while her teenaged son sat nearby playing video games on his tablet. This could also fall under "plot hole" because having the son close by made him available to try to help his mom when Pryce attacked her (with the intent to rape). (00:36:40 - 00:37:15)
Stupidity: The ending has a bit of a twist; apparently, octogenarian college professor Morgan Freeman somehow chased down and murdered offscreen 6'3" professional assassin Vernon Davis. That's not the toughest part to swallow, though; he also sent the two detectives (one of whom he is not even supposed to know of) via UPS 2-day delivery mail some body parts of his victim. We don't know which part Lavazzi gets (genitalia were mentioned earlier), but Boyd gets the eyes and decides to eat them. For starters, unrefrigerated 2-3 day old eyes would never look as pristine as the ones Boyd gets. Also, Morgan Freeman mentioned earlier in the movie that for the power of Muti to be effective, the body parts need to be taken from a victim that is alive, screaming, and eaten only mixed with herbs and other catalysts. So what the detective does doesn't make sense even in the movie lore.
Stupidity: When Drake cuts off power to Hayes' apartment, the cops can't physically make a landlord abide by the laws, and seeing a judge would take months. In the meantime, by keeping the power off in the apartment, Hayes would have had no choice but to abandon his scheme and move on to another victim. With no power in the apartment, it's unusable and unlivable.
