Stupidity: Billy gave Skylar (a stranger at the diner who did a "dine and dash", not paying $12 for her food) a ride. She came across as suspicious, angry and "street smart." Billy nevertheless put his envelope containing $500 cash between the driver's and front passenger's seat where Skylar could see - and take - it. When they arrived at the Kite Skating site, Billy got out of his Jeep without even thinking about the money. (Skylar gave the money back, but it could have been kept). (00:19:19 - 00:20:35)
Stupidity: Royce, blinded in Afghanistan, managed to avoid serious injury when the boat finally hit land. Having no real idea where he was, he foolishly decided to get off the boat and try venturing through unknown woods with the dog Chinook as a guide (!) This was simply absurd! Even though rescue missions were delayed that day by the storm, he should have had enough sense to know his chances of being found/rescued (and being safe in the meantime) would be the greatest by staying in the boat.
Stupidity: Why would the tow driver go around Deacon's truck in the one-way dead-end parking lot to pick it up from the front? He'd have to back it up on the hook, and Deacon's truck would be in Park, making it impossible. There's a reason tow trucks hook up vehicles by the drive axle ends. (00:08:40)
Stupidity: For someone trained like "H", it was absurd that he would run down the center of the road toward masked gunmen and get shot multiple times. It was also ridiculous for him to have taken his son to a location that was potentially dangerous and put him in harm's way in the first place. (01:13:20)
Suggested correction: I'm not sure how much H was trained. If I recall correctly he's a skilled criminal, and all his "training" was faked so he could get the job with the company. Regardless... training or not, all that goes out the window when your child is being attacked. Paternal instinct took over and he was rushing in to protect his son. As for your 2nd point, it's made clear that his task was to simply stake out what was supposed to be a routine truck route. They had no idea the truck was going to be robbed.
Stupidity: There were three vehicles parked in front of Rosie's Cafe when the Virtuoso arrived before 5:00 PM. As he walked past the vehicles, he surreptitiously took photos of the license plates to help him identify the likely target. The Waitress' Jeep was parked apart from these vehicles, on the side of the restaurant. The Virtuoso went by the restaurant's front windows where the target possibly could see him and took a photo of the Jeep's plate. (The fact that no-one noticed is irrelevant).
Stupidity: The Analyst wishes to hide the true identity of Neo from anyone inside the Matrix, so his appearance is altered. But in this new Matrix Neo is also named Thomas Anderson, his name from before he was pulled from the Matrix originally, and he is a famous game developer that created a video game series called "The Matrix." It is frankly astounding that anyone actively looking for Thomas Anderson would not immediately see through this ruse and instead would be fooled by balding hair.
Stupidity: Jennifer sat on a bench in the hallway while her arguing parents and maternal grandfather were meeting with a negotiator about the divorce settlement. The door to the meeting room was left open, allowing eight-year-old Jennifer to hear everything. Parents Maggie and Jeff also frequently argued at home when Jennifer was within hearing distance. Parents - especially one educated as a lawyer - should know better. (00:10:56)
Stupidity: David and his partner Cal drive into a weeded area near the garage/warehouse the drug bust is going to be made. David says, "This might go south. We need backup." David and Cal sit in the car talking about not letting the product get onto the street where someone might die, etc. then exit the vehicle without calling for backup, which could have been done in a few seconds (and should have been done as soon as David said they needed backup). (00:02:10 - 00:02:37)
Stupidity: Two oil rig workers were looking at two young ladies in bikinis who were sunning themselves on a boat/yacht. One oil rig worker said, "That's where we should be right now. With them, enjoying the sun, instead of baking in it." Both men had double layers on - a jacket or sweater over a jersey or T-shirt - and one man was wearing a tossel cap. Even if it gets cold on the rigs at night, they did not need to be dressed in warm attire during the sunny daylight hours. (00:10:35)
Stupidity: Simon sees his wife has been killed by a dinosaur, so runs out of the shed and tells Mark to run. Simon gets Mark into the front seat and hears the T-Rex roaring nearby. Instead of getting into the car as fast as he can, Simon takes the time to buckle Mark's seat belt and tell him to "be brave for daddy" and "everything's going to be fine." Simon turns around when the T-Rex is next to the car and he tells Mark to close his eyes. Simon just stands there as the T-Rex gets closer, then eats him. (00:05:50 - 00:06:21)
Stupidity: Right before the movie's final battle, Sub-Zero taunts Cole with his wife's necklace and makes him chase him into a portal. Sonya was right next to Cole, and she did not come along with him. They had previously planned to take on Sub-Zero together, but apparently she just left him to chase Sub-Zero alone to an unknown location.
Stupidity: When the thunder/lightning starts, Hannah correctly tells Connor "We gotta get downhill." Then she tells him to run and stop, plus shows him to crouch down. Granted, they needed to act fast, but her instructions were poor for someone supposed to be trained in safety. Crouching should not entail placing one leg from the knee down onto the ground - only the balls of the feet should touch the ground and the heels should be together. She didn't tell him NOT to lie down, but he was when he fell. (00:53:14)
Stupidity: Jon and his sister drove some distance to Bolton to find Janet, but Jon couldn't remember the name of the mini-mart where Janet works. Jon's sister said, "Maybe we should visit every market in Bolton", to which Jon replied she was a genius and "that's what we'll do." Instead of finding a telephone directory and making calls (first starting with Janet Brown!), they drove within a 10-mile radius, stopping at every store (not just mini-marts), but still could not locate Janet. (01:19:55)
Stupidity: The "body armor" General Ford and others wear is very bulky and appears to be quite heavy with all the attachments (e.g, flashlights on shoulders). With the protective suit protruding perhaps 8", it would most likely restrict/slow movement, contrary to what soldiers need. Moreover, the body may be protected, but there's no protection for the face/head, leaving them exposed/vulnerable. Today's products tend to be lighter, thinner, and stronger, so would be expected in the future.
Stupidity: Lyla does not like the idea of Mickey fighting and initially does not want him to agree to the fight. Lyla eventually tells him "okay", but he must stop when she tells him to stop. This may give her a reason to go to Dubai, UAE with him, but she is about 8 months pregnant. An international flight has some risks plus she would be far away from her OB-GYN doctor if there were a complication. She should have had enough sense to avoid international flights/traveling so close to her due date.
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: Two things: 1. I find it inconceivable that there is only one Carbon Dioxide Removal Assembly (CDMA) and no spares for a two-year mission. 2. The crew has 20 days to fix an oxygen problem. The commander decides on a 10-day window. 5 days into that window they try to load oxygen from the Kingfisher spacecraft. One is lost into space. Zoe decides to go and fill the other one in the midst of a solar storm that will only last hours. Why take that chance? A few hours wait is still quite possible.
Stupidity: Colette was holding the metal ladle close to the bottom of its long handle and near the top of the hot pot of stew she was serving, and yelled, "Ah." due to her hand getting too hot. She had a towel wrapped around the handle of the pot, but it was that hand that got too hot/burned (not the hand that was holding the metal ladle close to the top of the steaming hot pot of stew). (00:04:48)