Girl Trouble / School Dance - S3-E18
Stupidity: Girl Trouble: Helga pulls a nasty prank on Arnold in class by gluing feathers to his bottom. Mr. Simmons sees this, but for whatever reason, does not give Helga detention for it. The next day, Helga spills paint on Arnold, then he throws some on her as revenge. Mr. Simmons sees this and gives Arnold detention even though he was simply fighting back at Helga for pushing him too far. Perhaps Mr. Simmons' brain was on vacation those two days. (00:03:16 - 00:08:42)
Stupidity: Roberto Hongo is the center forward of the Brazil national team, and as we see from Tsubasa's poster/magazine, he did not alter his appearance except for wearing a fisherman hat sometimes. Despite being surrounded by football fanatics, he manages to keep a fairly low-key profile and it's totally not a big deal to have a top tier footballer hanging around the small prefecture.
Iron Man to the Second Power: Part 2 - S1-E10
Stupidity: When the other heroes are watching Iron Man battle his robot duplicate, Julia cheers him on and calls him Tony. This fight is taking place in full view of the public, and the public doesn't know that Tony Stark is Iron Man. They believe that Iron Man is Tony Stark's bodyguard. Julia could have easily revealed Iron Man's secret identity in this moment. (00:17:50)
Yomigaere! Eiyuu Densetsu - S1-E1
Stupidity: Despite being in training for 6 years at the temple to compete for a magical armor consecrated to a constellation and meant to harness the power of the Cosmos, Cassios and everyone else but Marin (Shaina towards the end) are mistified about the whole idea when Seiya uses it. What in the world have they all been training for, for 6 years, then? Shaina has to be the worst trainer ever. Cassios even calls it a 'superstition', but his master Shaina channels the power perfectly. It's like a Muggle working at Hogwarts and not believing in magic.
Stupidity: The ghosts should've noticed the money they were stealing from the US Mint hadn't got its serial numbers and Treasury seals yet.
Tough Love - S2-E43
Stupidity: When Syrus beats the Obelisk Blue student, the student throws him his GX medal. When this happens, the two are standing on rocks in between the ocean, and could have risked the GX medal falling into the ocean when it was thrown. It would have just been easier for him to hand Syrus the medal personally. (00:00:32)
The Ringer - S1-E1
Stupidity: As Link is watching Zelda from his tower, he's completely distracted and oblivious to the Moblins entering his room from the floor. They have the element of surprise and one sneaks up behind him. But rather than doing the smart thing and say, stabbing Link in the back or delivering a crushing blow from behind while Link is unaware of his presence, the Moblin simply just grabs him on the shoulder and puts his arms behind his back to hold him while the other Moblins go for the Triforce. Giving Link plenty of ability to kick one in the face, free himself and grab his weapon to fight them off. The Moblin should have just gone for the stealth kill, even if they aren't all that bright of an opponent. (00:02:10)
Stupidity: Shaun thanks Seiya for revealing the weak point of the armors of the Black Knights, but Seiya didn't actually do anything; the armor malfunctioned on its own. If Shaun is able to deal strikes with her chain precise enough to target a small box on the back of the enemy's neck, one would argue that she could have easily hit any other vital point the armors leave completely unprotected - especially since she showed also that she could elude their shield commanding the chain to take a sharp turn around it - which hit the supposed weak spot but didn't do anything, contradicting what is shown later.
Stupidity: While flying over the jungle in the Dragonfly, Dr. Quest uses the Dragonfly's speakers to tell the Po-Ho tribe he is their Air God and is angry for the tribe taking hostages. While he was at it, Quest should have ordered the Po-Ho's to release the hostages.
