The Secret of the Unicorn: Part 2 - S1-E4
Stupidity: When the Bird brothers are searching the treasure room for Tintin, one of them claims they have found him, and points. The other brother then shoots at him which was turns out to have just been a mirror reflection. The brothers then proceed to find Tintin and start by going straight forward, completely in a different direction than the mirror. If they wanted to find Tintin, wouldn't the more logical thing to do be simply look in the direction the mirror was pointing at? The whole point of a mirror is to reflect what is in front of it, so Tintin would probably have been standing in that direction anyway. (00:37:25)
Stupidity: When Eddie finally finishes installing the VCR and it explodes, they get a man out to repair it. However, Eddie had previously told Richie that he'd stolen 60 VCRs; 17 in the living room and another 43 in the attic, so they could have used one of the other 59 and saved themselves a crate of Malibu.