The Big Bang Theory2007

Leonard Hofstadter:
I deliberately tried to sabotage Stuart's date with Penny.

Rajesh Koothrappali:
Of course you feel terrible. You completely screwed up your karma, dude.

Sheldon Cooper:
You don't really believe in that superstition, do you?

Rajesh Koothrappali:
It's not superstition, it's practically Newtonian. For every action there's an equal and opposite reaction. Leonard pretends to be a friend and acts like a two-faced b*tch. Therefore, he is reborn as a banana slug. It's actually a very elegant system. You know, what goes around comes around.

Howard Wolowitz:
[motions Raj to return to working on the space toilet] Speaking of what goes around comes around...