Dickbugs broke me. It's the only episode I wasn't able to finish, and I'll never go back.
Honorable mentions to There's a Reason We Don't Do Drugs Together for the part about sounding, and Knowledge Is the Disease, I Have the Cure for the part about picking at teeth
I would put Achtung! Adult Babies and We're Gonna Need a Bigger Scrote on here but I've listened to those so many times it barely even gets to me anymore. That's my fault though, not the content's