Stupidity: Yoshi, Mario's sidekick who constantly follows him on dangerous adventures and has gone on dangerous adventures by himself, gets scared shitless when confronted by Riptor. This is not how Yoshi would act in a situation like this.
All Politics is Local - S1-E24
Stupidity: At the end of the episode, Joey and Melissa are in the kitchen, discussing Melissa's father. A small pot on the stove is very full of broccoli; almost overflowing. It makes no sense that Joey - who is a proficient cook - would be trying to prepare that much broccoli in a pot of that size.