Ayaushi shiryu! Cloth no hakaba - S1-E10
Stupidity: Saori blushes when Seiya opens the door shirtless...but she's seen him shirtless practically all her life, the boys kept training and fighting all the time. He even fought shirtless for the last part of his duel with Shyriu just the day before.
Stupidity: Why do they always have to go through that washing machine setup in the laundromat when they have a great functioning elevator to the lab?
Suggested correction: Why would Gus go through the process of hiding the lab entrance stairs behind a washing machine but leave access to a freight elevator wide open? The elevator would be just as hidden and probably locked up. Not to mention it would be slower to take than simply walking downstairs.
Stupidity: Andor and Luthen set a vehicle to drive and distract the security team. The vehicle is destroyed, and they immediately round the corner in full view of the team on a speeder and drive away, then blow up the vehicle. They could have driven away on any number of other streets without revealing that they weren't in the vehicle, keeping their escape secret. And if they blew it up before the team looked too closely they might have even been deemed to have been killed in the crash.
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.
Episode #1.7 - S1-E7
Stupidity: When Eugene approaches Tsuda after Tsuda is shot by Ae-sin, Tsuda attempts to shoot him, but after pulling the trigger, he realises there are no bullets in the gun. Seconds later, a group of soldiers run up to him, and he attempts to shoot them, but he can't because the gun is still not loaded. Something he should have known since he only just attempted to shoot Eugene and failed because of it. (00:50:00 - 00:50:30)
Stupidity: Linda suffers a gunshot while in the hospital. The doctor calls for a trauma team that responds immediately to take her to surgery. The next time Linda is shown the trauma team is still taking her to surgery through the hospital hallways, and the whole Reagan family made it to the hospital and in the hallway as Linda is being taken to surgery. The hospital hallways must be long or the trauma team took the long way to surgery to allow the family to be there. (00:03:28 - 00:05:57)
Stupidity: Mouch is investigating an arson allegation. He states to a lady he's going to do his thing and speak to some of the residents. As he goes down the hall to speak with the residents he passes a huge stain on the carpet that looks like blood or something and walks right past it without stopping. (00:23:57)
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)
Log 81: The Long Walk - S1-E14
Stupidity: They are looking for a red convertible. No other description of the car. A red convertible pulls up behind them and passes them. The ragtop roof is up but it's still matches the description. Doesn't faze them in the least.
Stupidity: When Kunte/Toby saws himself free from his leg irons, he removes only the one, and then runs off into the night, dragging the other one behind him, which makes no sense, and is quite audibly heard in the near distance.
Living Hell - S1-E8
Stupidity: When the villain reveals to the doctor that he plans to transplant her brain into his own head, the doctor tells him it isn't possible because the brain can't survive outside the head. Forgetting to mention the fact that he will die the instant he takes his own brain out, making it rather difficult to complete the procedure, that is, if he didn't pass out from the pain of opening up his own skull first.
Siege Protocol: Part 1 - S3-E11
Stupidity: The team is going on a CQB raid to free some hostages; so close quarters battle, room clearing, a very high chance of getting shot since the enemy can hide anywhere. They are not wearing plate carriers and their armor. This is the very mission that military doctrine emphasizes armor. It's not a long range patrol through mountains where weight matters. However on a previous mission to locate a downed pilot in open terrain they were wearing plate carriers. (00:27:12 - 00:28:00)
The Stripper - S1-E3
Stupidity: The whole plot resolution can happen merely because, on top of Matlock's unbelievable guess on how to trigger someone's dormant personality - apparently murder wasn't enough, but a joke is - the transvestite has two entirely separate voices, one of which is a dubbed-in female one. Not quite believable even for the times.
Stupidity: Radar takes his glasses off, takes a sip of coffee, then props his clipboard onto the typewriter and accidentally starts typing on the desk calculator. Even if he didn't know his desk well enough to wonder what he laid his clipboard upon AND was so blind he couldn't even orient himself by the desk lamp (which he isn't), he would have felt the difference the instant he touched the keys. Note that he puts his hands on the keys, squints at the clipboard (sic!), then starts typing, he doesn't hammer away right off, which would have added at least a little plausibility to the joke.
Stupidity: The brothers are angry at Leo because they say he's responsible for them dying because he chose to save other soldiers instead of them, Leo also blames himself for the same reason and says he should have stayed and gotten them out. But in the flashback it shows Leo helping them and then running off to help other soldiers, after he runs off the brothers are killed just a few seconds later. Even if Leo had chosen to stay with the brother he couldn't have gotten them out in time, the only difference would have been Leo would have died with them, but Leo dies in the same war so he didn't live much longer. Leo's guilt and the brothers' blame don't make any sense at all.
Welcome to Hotel del Luna - S1-E1
Stupidity: The Mayor realises that Man-wol has approached him and taken out her rifle to shoot him with. Yet during the entire time she takes to aim the rifle at him and fire, the Mayor makes no attempt to flee the stage for his own protection. (00:38:15)
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)
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).
Stupidity: S1E8 Obsessed - Morgan and the detectives respond to the beach for a possible homicide. None of the detectives or Morgan are wearing protective gloves. Throughout the series, the detectives remind Morgan to wear gloves before touching evidence. However, she takes the pulse of the victim without gloves. (00:04:02)