I did a couple of times because I thought that was what boys where supposed to do, punch people in the face at the slightest provocation.
Funny though the respect it gets you, one became my best friend, the other relating how far he had been knocked along the corridor as if I had just performed some note-worth feat of a sporting nature, worthy of admiration I still have the scar on my knuckle.
Maybe it helped me not get bullied because it wasnt the real me as Iam a cowardly wimp inside who occassional tries to be brave.