I had a friend who aspired to be a stand-up comedian. Everytime we would hang out he would test his shitty jokes on me. Over and over again. I swear, he would tell me the same jokes dozens of times in order to get feedback or something. I heard his jokes so many times I could do his routine by memory. I hated being his guinea pig, but he never stopped.
Anyway, this loser signed up for his first amateur comedian night and invited a few people, including me. During his set, I decided to mess with him and yell out his punchlines mid-joke. He got so completely flustered he literally RAN offstage with tears in his eyes. I haven't seen or talked to him since (this was like a year ago), but that shit was hilarious. That's what he gets for constantly using me as a test subject for his bad jokes. Hahahaha.