Stupidity: When Roy finally gets to the Lima project in the shuttle but can't dock, he just lets it drift away - he could have at least tethered it to the station to use it for his return trip.
Suggested correction: There is no way to know the reason why he did this. It's plausible, or even likely, that the pod was out of fuel. Not only that, but it could not dock with Lima because it was damaged, so it's likely that the damage played into the decision as well.
Stupidity: In the opening scene with the military convoy, the two soldiers in the lead vehicle never notice the car veer into their lane, even though their faces are bathed in bright light from the car's headlights. They simply ignore it and keep talking to one another.
Stupidity: Adam, Hannah, and Megan [sitting in SUV with flat tire] saw the Man flashing his headlights, getting out, kicking his own SUV and ranting while holding a machete. Instead of fleeing, they got out of their SUV and saw the Man was wearing a welder's mask. When they returned to their SUV, they didn't lock the doors. The Man ran over, pounded on the front passenger's window and then opened the door. He stabbed Adam 36? times while the two girls just sat there screaming and one said, "Please stop."
Stupidity: While Tommy and Snake Eyes are trying to escape the docks in the truck, the Yakuza men surround the truck and stab over a dozen swords in all parts of the cab. Not one of the men ever thinks to use their sword to slash the tires, allowing the heroes to make an easy escape.
Stupidity: The whole premise of the plan is summarized by Helen in the sentence "They don't know Andi is dead, so why would they suspect anything?" However, "they" conspired in unison to financially ruin her sister, and "they" did not answer the mail, none of them. The possibility that "they" all could have gathered and silenced her by force is one of the most likely ones, and yet neither she or Blanc consider even for a moment that the literal crime conspirators could have conspired.
Stupidity: There is no reason why any person as intelligent as Janet would keep the knowledge of Kang secret from her family. The extended Pym family are the only people in possession of the one thing Kang needs to escape. The brief explanation she gives is that she wanted to protect her family, but this makes absolutely no sense whatsoever, and she makes no attempt to explain how this secret keeps anyone safe.
Suggested correction: She is obviously scared out of her mind concerning Kang. She, through her fear, had hoped that him being trapped in the Quantum Realm would stay permanent as long as nobody knew about it in the normal universe. In that way, she tried to protect not only her family but the entire universe.
Not only does she not say that she is "scared out of her mind", she also doesn't act like it either. There is no indication that she is so frightened by Kang that she has lost her senses - quite the opposite, actually. She appears to function rationally and intelligently in every other area concerning Kang, except of course for simply telling anyone how dangerous the Quantum Realm is because the movie wouldn't have a plot otherwise. It's pretty egregious and wildly ridiculous.
Of course, she doesn't say that or act like that. But what she saw of him, when she touched his ship, scared her enough to go to all that trouble to keep him in the quantum realm at all costs. She thought it would be safe to leave, that he was trapped forever. Her judgment was wrong, probably caused by her fear. She is only human.
"Fear" is not enough to get past this level of stupidity. My point is that she doesn't act so frightened; she isn't irrational in any other way. It's just a flat-out, stupidly written element of the film that is impossible to believe. There is no way on God's green earth she should keep this secret, even after her family has made it to the quantum realm. I get that the movie is trying to say she is frightened, but this goes well beyond making any kind of sense at all; it's ridiculous.
Part of the stupidity also involves Janet's action in the mid-credit scenes of "Ant-Man and the Wasp," where she actively helped send Scott into the Quantum Realm to get quantum energy. If she was so afraid of a signal being sent to the QR, she wouldn't have let Scott go without explaining the dangers of going. This film seems to ignore that and instead seems to focus on Janet simply not wanting to discuss her involvement with Kang and her guilt, thinking no one would go back to the QR.
Stupidity: When Wolverine is trying to prevent Deadpool from sacrificing himself by destroying the time ripper device, he repeatedly pounds his fists against the glass panel on the door to break it, to no avail, which leads him to then go to another heavy door, which he is only able to break down in the nick of time. Wolverine's adamantium claws would have easily destroyed the glass on the other door, without him having to repeatedly and futilely punch it.
Stupidity: Kord Headquarters goes into "lockdown" after the Scarab is stolen, which in this building, apparently means allowing all the guests to leave.
Stupidity: When an explosion hits the courtroom, Arthur is the closest person to it, with nothing to protect him, but he is the first and only one to recover, and every bailiff (not to mention the police outside the courthouse) outside of explosion range is mysteriously knocked out and/or absent.
Stupidity: The team can hack security cameras and gain access to Pam's laptop easily and load the image they want on her screen, but then have to email it to themselves for some reason rather than just transfer the file directly via the connection they already have to her machine. Ridiculously insecure and an unnecessary step.
Suggested correction: You're not wrong, but that segment is far more flawed. In reality, hackers never use the "remote desktop" technique, which has high bandwidth overhead and would require constant distraction of Pam to prevent her from noticing the blatant intrusion on her screen. Real-world hackers typically open a file-sharing connection to analyze the victim's PC, avoiding any interaction with the screen, mouse, keyboard, or email address.
Stupidity: During the auction, we see the dinosaurs are brought into the room and placed in the middle. Thus blocking half of the bidders from the auctioneer's view. (01:16:40)
Stupidity: Colonel Sharpe retrieves a gun from a locker on the Freedom shuttle. However, said gun is shown lying flat on the floor of the compartment, with no visible means of securing it, which would hardly be standard NASA procedure given the shuttle undergoes a high-G launch, orbital manoeuvres and various other high acceleration events. A loaded gun bouncing around is the last thing anyone would allow on a shuttle. (01:42:39)
Stupidity: Red and his gang have a barn full of stuff and talk about other couples and people they have kidnapped, robbed and probably killed. This indicates they have been in the "game" for a long time and been successful to avoid capture this long yet when Kurt Russell didn't want to get in the car, instead of cutting their losses, they went along with kidnapping his wife and initiating the whole ruse of her never getting in Reds truck which is what led to their downfall. Someone with the experience of this that Red has should know not to take such a big risk with a complicated story.
Stupidity: Jack has been using Mosley's badge and identification to pass himself off as FBI. He never once uses this trick to commandeer a civilian car for him and John when it would have been the safest way to get to L.A. much sooner.
Suggested correction: Probably because If he did that, the car's owner like Red the bar owner would eventually call the FBI office to get their car back and then the feds would know the make, model, license plate, and the last location of Walsh and the Duke. The police would have caught them in minutes. Walsh had to keep a low profile.
Stupidity: Mike Roark is supposed to be the director of an agency that is in charge of coordinating all the resources of the city in the event of a natural disaster, but he doesn't know what a "geological event" is, not to mention magma?