I can't decide.
One time my brother was arguing with me while I was trying to get to sleep and I just said "would you shut up for once in your miserable little life. Nobody cares what you have to say." That shut him up. He has never treated me the same since then.
or
Same brother was asleep on the couch and I went up and put all my strength into a punch to his nuts. he woke up screaming.