What is the point in being mean to people?

I don’t get it. Why would you ever be intentionally mean to people? Like not getting people back, like for the sport of it? What do people get out of it? Is it dopamine? Isn’t it stressful to carry the weight of doing something deliberately mean on you?

This isn’t some weird teenage philosophical question where I’m trying to be fake deep— I’m wondering if any of you have insight into how people who like to be mean work. Like what drives their impulses? Is there any neuro research on what being mean does to the brain?

This may or may not be a stupid question