Stupidity: I won't begrudge Father Lamont for instinctively grabbing for the first thing in reach to try to smother the box on fire (even if it is a pair of wooden crutches), but you'd think at some point he'd notice that he's just spreading the fire and making it much, much worse, but he keeps at it until the doctor finally returns with the extinguisher.
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.
Stupidity: It's very idiotic that Michael and Karen kept the same security password, even after being harassed and not feeling comfortable with Pete being around them any longer. There's no way the pyramid password should have been kept the same, with Pete being able to enter their home, plant drugs, and frame Michael. Changing your security password, the same password that the lunatic cop once knew, would be the first thing to do after his psycho behavior starts.
Stupidity: When Will Smith and Gene Hackman are running through the railroad yard. Gene calls Will by his real name, "Will" and not by his character's name "Robert."
Suggested correction: You could be a little bit more specific, but I don't hear him say "Will" at any point during that run.
Stupidity: It was very idiotic of Turner, who is an experienced serial killer, to not only knock out and take Julie prisoner, but to attack Kale as well, considering the recent circumstances. The police and Julie didn't believe Kale, and Turner suddenly goes on a rampage? He took a huge risk when he attacked Kale and could have very easily blown his cover.
Stupidity: Rick tries to kill Frank at his boathouse by dumping gasoline all over the place and using Ray Coleman's lighter that Frank had. At this point, Rick has gasoline over his arm, but instead of properly cleaning it, he opens the lighter immediately and has his arm burned. Surely a criminal genius like Rick wouldn't have risked this as this is a loose end. Further mention goes to when he has the bathroom door open for no reason while medicating the burn mark, which enables his wife to see him and discover who he really is.
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: At the end Vince fires a grappling hook at the passenger seat of the truck then attaches the other end to himself, all the truck driver has to do now is hit the brakes and Vince would be dead under the truck or dragged along the road.
Suggested correction: In point of fact, the truck driver does slam on his brakes; but, defying physics, Vince is catapulted around the right side of the truck to the passenger door.
Stupidity: When Sook-Hee and Hideko are leaving the mansion to meet up with Fujiwara, they run past a rope and noose tied to a tree. Later on, it's revealed that this rope was tied to the tree because Hideko attempted to hang herself. Despite abandoning the suicide attempt and coming up with a new plan to scam Fujiwara, they leave the rope tied to the tree, even though this could potentially expose the scam to someone at the mansion. (00:53:32 - 01:47:15)
Stupidity: Scott spread his lie about the protagonist telling Dean, who tells Frank (without details, just that the guy is 'a good fighter'). So barely one person (acting rather childish for a supposed master) has any animosity towards the new fella. There are over two dozens people in the class (in a 'good guys' gym, not one of those evil moustache twirling villain dens) and yet everyone is happy and cheerful watching a black belt beat the snot out of a schoolboy redbelt, for no reason. Most people there are grown-ups and there are black belts; they should be horrified or at least VERY puzzled. (00:30:00)
Stupidity: At the end, the police inspector talks Bruce Lee into surrendering, and about 8 people (including the inspector) escort him out of the school. As soon as they're outside, Bruce sees a formation of heavily-armed police preparing to fire. Realizing he was betrayed, Bruce Lee charges, screaming, straight into a barrage of gunfire as the action freezes for credits. However, before the action freezes, there's NO reaction from anyone standing behind Bruce Lee, even though they are directly in the line of fire. Even the police inspector (who knew the police gunmen were waiting outside) just stands there instead of immediately diving for cover.
Stupidity: There is a scene about a null hypothesis proving Cassius is the killer. Nearly everything is wrong in this scene. Statistically, you never prove a null hypothesis true. (01:23:11 - 01:24:22)
Stupidity: When she leaves him at home with a sandwich she says people will come check on him. When she gets home and he's not there, she doesn't go and ask those people where he is.
Stupidity: I seriously doubt that any Mexican Mafia cartel operating here in the U.S. would waste their time eliminating two simple patrol officers. There's nothing to gain by doing so, and it would bring a war between themselves and the police, which in return would bring hundreds of arrests of key members, drug busts, raids of their operations within Southern Cali, etc. They wouldn't risk their business taking millions of loss of revenue all to kill two patrol beat cops.
Stupidity: In the bar scene, Jack gets into a fight with a guy he busted a few years back, then Reggie turns to the bartender and asks for a gun. The bartender hardly hesitates and hands it over. There is just simply no scenario where a bartender would hand a loaded gun to a patron they had just met.