from my childhood you guys would definitely not approve of, in light of the information in this thread.
When I was 5 years old, I was playing on the playground one time, and a larger, older boy started picking on me, verbally and physically. I started crying. His mom, in an act of fantastic parenting, was smirking and not doing anything.
My dad, who's a lifelong pacifist and a very calm person decided to not resolve this issue as an adult. Instead, he got into the other kid's face and said, "if you don't stop picking on my son right now, I'll rip your head off and put it back on backwards, and you'll be that way for the rest of your life".
Needless to say the kid stopped.