Ya... Most are single punches with guys not defending themselves adequately. As I get older, I find it troubling to see younger people not even try to talk it out at all. I'm getting old and I worry for my own children. In my Dad's generation, they would have met at an assigned time to "settle their differences"... The fight was over the second the other guy went down. No late shots or kicks to the head. You had a milkshake with your poodle-skirted girlfriend afterwards.
Anyways, I always found the really nasty guys did the 'push' and lead with a headbutt and then went for the knees/take-down to slam your head into the ground. The second you tried to defend, you had to protect your chin and be moving backwards with your legs splayed out... The really fucked up guys went for body blows to the liver area... Evil mofos! That's where I drink out of!
We are all animals. Someone is always bigger than you are or more crazy. Just a matter of time.