I think my stupidest fight was a physical one when I was a kid, probably about 13-14. I was in the school library with a classmate (I think "friend" would be putting it too charitably

), all chill, when suddenly, and for no apparent reason, he threw a punch and hit me in the side of the face.
It didn't hurt. But there was a bit of a crunching sound; I asked him quizzically whether it was his fist or my face, and he responded by holding his hand and screaming a bit, so I guess that answered that question.
As we left the library, I was trailing a little behind him, and he spun round to deliver a roundhouse kick in the direction of my head. I caught his foot just in front of my face, held it a second, then pushed my hand up, which sent him toppling over.
He was an odd lad, that one.