Your Experiences with Sibling Rivalry?

I was one of two boys in my family and there was always rivalry between me and my brother.

I'm now a 30 year old man and we still get into these weird child/caveman like battles. Just last week, as soon as I walked into my brother's house. He grabbed me by the neck and tried to slam dunk me on the coffee table. I kicked him the nuts in retaliation. Meanwhile his wife asked me if I wanted tea.