Tweek, easy. Putting aside how he's just the same gag over and over, I genuinely feel sorry for Craig for having to deal with his nonsense on a regular basis. The first time my partner came into my room screaming about how North Korea was after THEM specifically, I would start planning ways to fake my death and run for it.
Sheila Broflovski. Dear god in heaven Sheila. The woman is the Omega Karen. Who else starts a war with Canada because her kid started cursing and telling foul jokes?
Kevin. Just...goddamnit Kevin.
Thing is though, it's Tweek. There's no telling if that rocket was real or him going bonkers. I know the Underpants Gnomes thing was true, but there's no telling how often the kid's cried wolf.