All I know that usually when you took alot of punches in your lifetime, then when you get punched you generally get pissed off, or your blood starts to boil a little. You have that "he hit me? well I wanna hit him back." mentality going. You dont get scared, run and cover into the fetal position. Its a good example of the fight or flight brain response. If you are accustomed to it, you are more likely to just fight it. If you arent used to that situation then your instinct is to run. Again its like touching a hot stove. When you cant handle the pain, you pull back your hand almost the second you feel it. While others try to tough it out and see how long they can hold their hand on it, and can leave their hand longer than others. I know im just blabbering now, but you get the idea.