I wouldn't be able to recount how many times I have witnessed bullying. I witnessed bullying of people who were just not good at responding to bullying. That included not only other kids, but teachers as well. One of primary school catechesis teachers (catholic teacher before baptism) was bullied. People would throw paper balls at her, laugh in her face etc. I don't know what happened to her. Then on my very first day of junior high the teacher responsible for my class had a mental breakdown and started to cry because of a conflict with one of girls in the class. She, the teacher, beefed up after that and tried her best to make anything out of the class. I think it was her last class assignment before she retired and I'm really grateful to her for trying. In the same junior high class, bullying didn't spare even "alpha males". One of alpha males and bullies was reduced to an underdog, because he was suspected of cooperating with police. He would be beaten if he tried to wait for classes in physical proximity of a classroom. After some time he was moved to some other school. The same happened to another guy.
I was myself on reviving end maybe 4 times. I was humiliated for example by pouring a soda on my head. Although, one time when I was in primary school, it was more an assault with pneumatic rifle than bullying. I had no money, nor anything really valuable, so those two guys stole from me a knoppers (snack-bar)... Brothers of these two guys ended up in the junior high class with me.
Twice I ended up being part of a group that was bullying. Once in primary school, I wandered off after school with group of my class mates and they ended up bullying our another class mate. I was never very social so if I recall correctly I didn't even register that we were not just wandering around, but that they were planning a "setup". Another time I was at a birthday party. It was when I was in high school. I more or less knew what could happen, because certain guys were bragging about similar things. What happen was that colleges of my classmate decided to randomly assault pedestrians just for the thrill of it; they were not trying to steal anything from them, they just literally wanted to beat random people for fun. Me and the birthday guy had to force one guy to let this random guy escape. He was kicking that poor guy around head while the guy was on the ground. But again, bullying is not a good term here, it was a brutal assault. The guys should have ended up in prison. I should have reported it to police. But as I wrote, bad things were happening to people who were getting involved with police.
Mind you, I don't think I was in bad schools. My primary school was very much an average school. The junior high was in the same building, with the same classrooms, and with the same teachers as the best high school in the city. My high school was not the best, but the third best in the city out of maybe 20 other schools. Although, I think, my junior high class was an exceptionally bad class.