Ruined Childhood - One of the worst episodes in the entire show.

Oh, how I miss old seasons

Here's a brief plot summary:
Timmy tells Poof a scary story, and Poof keeps Timmy up all night crying about it. Then Timmy wishes for twelve hours with no light (I guess so he can sleep?). Then Cosmo and Wanda turn into "Scary Fairies" due to being in the dark too long and scare the ever-loving crap out of him. Except they weren't, they were just trying to teach him a lesson.

This is far from being the worst episode (the parts with Crocker and Tootie were funny), but I hate how uncharacteristically assholish Cosmo and Wanda are in this episode.