I was in a store one day and a father was repeatedly backhanding his son who was about 6 years old; full-arm-swing backhands! Why? His son needed to use the bathroom and interrupted his dad while he was talking to the store clerk. He got 4 good blows off, but I stopped the fifth one by blocking it. The dad looked at me, pulled his hand back and wound up to hit me. I told him to go ahead. I was smiling at the time. The guy stared at me with a hatred I've never seen before. He stood there for a couple of seconds, then grabbed his kid and left the store. The store clerk looked at me and stated, "You just lost me a customer." I said, "No, now you lost two", and I walked out.
That was fun. I really dislike bullies having been bullied when I was young. Nothing like a few years of martial arts to give you some backbone.