One of Shawn's points needs to be explored a little more...
Yes. Many of us, as children, played violent role playing (dramatic play) with our friends and siblings, such as cowboys and Indians, or war play. This gave us opportunities to hurt others and be hurt with limitations. That’s what play is for... it allows grown up behavior in a safe environment. I don't see children playing like this anymore. Parents are afraid to let their children play in the neighborhood, so the children play video games and watch TV and movies. They have very little positive social interaction.
When you were playing with your friends and things began to get a little rough, you let them know it and they let up. I obtained plenty of bumps and bruises from my best friends and they received a few in turn. That's how we learned restraint. You don't learn restraint from TV or video games, on the contrary; you learn to destroy without restraint!