Ant, the fact that you walked away is a huge sign of maturity on your part. No reason to get shot in front of your family because some stupid kid is trying to impress his friends. I used to love situations like this... as you grow older you not only become increasingly aware of all the ways it can go wrong... and you tend to look back and remember all the other similar situations and how lucky you were that they ended ok. I find myself doing that quite a bit now at 35.
Fighting belongs on the mat or in the ring
