You steal your friend's catchphrase for exactly two days before he starts using it back at you—but slower, louder, and with the kind of exaggerated eye contact that makes it clear he's not laughing with you, he's filing a lawsuit. By day three he's somehow made it his own, your friends are crediting him with the invention, and you're standing there realizing you've just spent 48 hours workshopping material for someone else's comedy special.