But they act like an ass for a reason. Bullies are bullied themselves, probably have lots of stressful things going on at home, might be going through family problems, maybe they lost a close relative. Sometimes bullying is a way for people to get out anger and sadness. It isn't a nice way, but, talking to a bully and hearing their side of the story helps.
There are some who find it fun, but many have problems that are so stressful and hard, that some people get their anger out by bullying.