What kind of mental disorder do I have?

In rl I'm a very calm and chill person, until you piss me off. I love seeing the fear in a person's eye's when I start yelling at them. It's like they're not use to seeing me angry. It's a pure thrill for me. I've even smashed a guy's laptop just to see his reaction (he owed me money). It was hilarious! It's funny because he keeps saying he'll fight me, but last time I saw him I just pointed at him and started chasing him as he ran off. It was hilarious!