Why do certain people have a desire to cause fights?

There are people out there who enjoy causing violence. They are people who think up lies to tell about people who they know, to get them all mad at each other and fighting. They often play off being drunk as their excuse for starting a fight. These loathsome people most often choose someone totally random, whom they target, and then make rude comments to them or hit them repeatedly to provoke a response from that person, leading to a fight. They don't seem care what happens to any the people they manipulate, as long as they can satisfy their own need for turmoil. They love to have fighting/bickering going on at all times around them and can't get enough of it, even when they are the ones involved in the fight. I detest such people, I know plenty of them, but I can't understand why they behave in this way or how their minds work. They puzzle me. What drives these people to seek to start turmoil and violence like they do? Why cause ripples where other people struggle to hold onto order?