I learned a lot about people's relationships to violence when making People Fighting, a big revelation being that folks want to be hit more than they want to hit. I didn't realize until after I witnessed this that I went in thinking "If I can get a black eye, I'll be happy", I didn't care about the damage I wanted to cause, just what I wanted to receive.
One contender didn't quite get the fight he wanted. Dylan had a simple request, to be punched in the head. I felt bad. I had asked him to volunteer his time, his likeness, and his dignity, but I failed to put him in the danger he wanted, so a few nights later I offered to hit him in the face to make up for it.
We went to his duplex's shared basement with a small audience of roommates and geared up to trade some blows. Even though I had no problem swinging to my heart's content with my opponent in People Fighting, I couldn't bring myself to throw a fist at Dylan. We stopped, this isn't working, and I asked him to hit me first, so I felt justified in a blow.
He swung once and I was too damaged to return the favour, so Dylan's dream is yet unfulfilled.