A Rough Whimper of Insanity - S1-E7
Stupidity: The hacker's VR goggles are not plugged in to anything (despite having a wire for this purpose) when he and Tom sit down at the computer in the teacher's house.
Day 4: 12:00 A.M.-1:00 A.M. - S4-E18
Stupidity: After leaving the power plant to pursue the terrorists and retrieve the nuclear football, Jack orders the helicopter to take out the first Jeep. After he realises parts of the football are missing, why does he not order the helicopter to pursue and take out the other Jeep, preventing any further trouble from Marwan? (End of season 4's story, most likely).
Who, What, Where, Wendigo? - S2-E10
Stupidity: Dwight, Audrey, and Nathan all know Dwight's trouble is that all bullets are attracted to him, so why is he with them when they go looking for the killer, knowing every one is using a gun?
And All Through the House - S1-E2
Stupidity: The woman could've blamed her husband's death on the maniac, she didn't need to go outside to retrieve his body.
Stupidity: When Brass and Sarah enter the locked storage cellar where the boys are hidden, Greg, a graduated rookie, straggles along behind them when he should have known better to stay put. As anyone could have come along and locked that cellar door behind them, trapping them inside.
Stupidity: Early on in the show Tony had a rule about talking business on the phones. He even scolded Tony Blundeto about talking too boldly on the phone. Now he's speaking with Sil on a phone openly about the FBI finding a body from 25 years ago. If the government is listening in he gave them all the ammunition they need to focus their probe. Even when they speak in code, the government has experts that decipher it and testify to its nature. They even used names which help identify the parties involved. (00:21:16 - 00:22:00)
Stupidity: While discussing his arrest with Emily, Seth mentions that he didn't tell the arresting officer that he works for Kirkman. As the White House's liaison to the media, Seth has a high degree of visibility; it would extremely difficult, if not downright impossible, to keep his place of employment concealed from the police for very long in the time between his booking and arraignment and when Kendra bails him out the following day.
Duel Distractions: Part 1 - S1-E36
Stupidity: When Bastion shouts during the duelling exercise, Syrus and Chumley fall over and drop their cards. About 15 seconds later, Chumley stands back up, but leaves some of his cards scattered on the floor. First, his cards could have got dirty or damaged, so Chumley deciding to leave them on the ground is very foolish. Second, Bastion doesn't seem bothered that the cards are still on the ground, despite the whole point of the exercise is about being ready for duelling. (00:04:05)
A Bad Reflection on You - S1-E38
Stupidity: The decision to risk revealing their identities to Bulk and Skull is one that the Rangers could have easily avoided. Since they tell the bullies to cover their eyes and ears, under the false pretense of a magic trick, they could have simply teleported to the Command Center, or any other secure location, and then morphed, well away from prying eyes.
Stupidity: Why does Jack Cassidy plant the lighter in the office when he could just pretend he has forgotten it? Does not make sense.
From Injustice Came the Way to Describe Justice - S1-E5
Stupidity: The police raid an apartment in search of guns. They should have used a ballistic shield for the point man to make entry and hit the apartment with a concussion device (flash-bang). The police officer who took a stomach full of lead would have more than likely survived had they been properly equipped. Ballistic shields have been around since 1977. This story takes place in 1992. (00:49:17)
When in Rome - S1-E3
Stupidity: A supposedly covert camera is placed in plain sight on a wall in a crowded room, with a prominent antenna showing, and a blinking blue light. (00:16:55)
Stupidity: "Rei" comes into the circle, having been champing at the bit to "turn him into a smear on the floor." She's wielding a sword, Kovacs is unarmed, and she...slices him a bit, instead of a quick killing blow.
Episode #1.8 - S1-E8
Stupidity: There's a gunman that just opened the school doors, and he's looking at the police like "a deer caught in the headlights" and they are all pointing their weapons at him and he's holding a gun mind you, but somehow these cops let him run back into the school without even taking a singe shot at him. His background was clear too, so if the cops fired there would've been no collateral damage if they had a shoot out. (00:35:00 - 00:35:30)