Funny / I Am Not a Serial Killer

The frequent Gut Punch moments and near-constant Nightmare Fuel do nothing to stop the series being hilarious(usually in a pitch-black way).

I Am Not A Serial Killer

• John's famous speech at the Halloween dance manages to be this, a Moment of Awesome, and Nightmare Fuel all at once.

Mr. Monster

• While it gets significantly less funny later, John's first scene with The Cat is pretty amusing to anybody who has a cat and has had this same interaction-nay, conversation with theirs.
• Forman imitating April.
  You learn a lot working at a police station, like the fact that a certain Mrs. Cleaver won't stop calling about her daughter's abusive boyfriend. 'Arrest him, shoot him, kill him!'
• John and Marci tag-team snarking on their friends is Hilarious in Hindsight.
  Rachel: This place smells green. And a little brown, because of the smoke.
  Brooke: Exactly!
  Marci: Can you believe these two?
  John: It must be some kind of shared delusion.

I Don't Want to Kill You

• Most of John and Marci's interactions, really, but especially John's horrible idea of what being a boyfriend is.
  John: This means I have to give you some kind of cutesy nickname, right?
  Marci: I don't think we have to go that far.
  John: How about "sweetums"?
  Marci: If you call me that again, I will find another date for homecoming so fast your head will spin.
• There's something absurdly hilarious about the whole concept of the climax. Nobody dies because she just wanted to get in John's pants that bad. Gotta admire the dedication.

The Devil's Only Friend

• John reaches critical pettiness by adopting a dog to annoy his roommate.
• His conversation over "the speed-bump test" with Elijah. John's problems are typically Played for Drama, so when he goes full Heroic Comedic Sociopath, it's absolutely priceless. And remember that all of this takes place in the middle of a tense firefight in a darkened Supervillain Lair.
  John: [about Elijah getting shot] You'll be fine. I've seen you heal from worse.
  Elijah: The only injury I've had that was worse was getting hit by that truck.
  John: And you were fine.

Over Your Dead Body

Nothing Left to Lose

• Three words: John + theatre people.