Why make friends with someone who treats you like shit?

I am reading the same book, Lost in Place, by Mark Salzman, and can say in the book I don't find anyone really an enemy. However I did consider Michael, the bully, a major enemy before they ended up becoming friends. Michael had these weird fixations on wanting to play these violent games, one of the most remarkable parts of him bullying our little hero Mark was when Michael was going through his BB Gun phase. They played an odd game that is just made up by sadistic people who get pleasure out of other peoples torment. "It was Michael, however, who had the revolutionary idea of using the guns to shoot at other kids. It began with a game called Execute the Prisoner. I, along with two other boys who were also not Ebers, was the prisoner; Michael was always the executioner. As prisoner, you stood next to the executioner and at a signal from a third person, you started to run as fast as you could. The executioner was supposed to count to five before pumping up his rifle and shooting you in the back. (pg. 75)" I learned to hate Michael for what he was doing to Mark and other kids, especially when Michael got bored and pre-pumped his rifle before hand and shot a kid point blank, however it wasn't Mark. I saw redemption in Michael in two accounts, one where he got the ever loving crap beaten out of him and when he said to Mark in the Kung Fu school. "Lets work out this afternoon (pg. 87)", and when Mark recalled from Michael during a night spent sleeping in a car, "Michael said that if he could live his life over agian, one thing he would definitely change was his decision three years earlier during out BB-gun war to keep that boy who had fallen through a prisoner in the abandoned chevy, 'No wonder that poor bastard was so mad,' he kept saying, his teeth chattering the whole time. (pg 106)" Michael redemption in my eyes, and befriending someone he harassed was most likely the best thing he's done in this book. Mark doesn't get messed with because he is with one of the "immortals", Michael is like a guardian angel.

I've had bullying problems in the past, but did I become friends with them? That answer would be no. I never did try to become friends with my bullys, hell I never wanted to be friends with anyone really. I absolutely despise talking to new people one-on-one, not so much hate when I think about it but more of just Wanting to talk to them, but Cant because I'm afraid of meeting new people. Eventually my bullies found they weren't going to get a rise out of me anymore, or I'd pull a gun on them (a common rumor spread about me because I was a quiet loner), some of it is also thanks to my smart ass mouth, where I got more of a kick of them trying to pick on me than the other way around. All in all, I never made friends with my bullies, but we were "cool" in a sense of don't screw with me, I won't have a reason to screw with you.