Answered on Quora:
It is not true that anyone can act this way. Most non-psychopaths will not behave this way. Most narcissists will. Many borderlines will. Histrionics might. Manics definitely will. This is Cluster B behavior.
When normals are cruel, which they often are, there is typically a reason for it. They think it is a good reason, but often it isn’t. I can’t imagine a neurotypical hurting someone out of boredom. That’s ridiculous.
Psychopaths and sociopaths along with narcissists are known for their cruelty. Borderlines can be exceptionally cruel, but they are doing it because they are crazy rather than because they are evil. Narcissists and sociopaths/psychopaths are getting a lot more towards true evil.
I had one psychopathic client in my counseling practice. This young man desperately needed an intervention so he didn’t kill someone for the sheer fun and thrill of it. This man told me that sometimes when he was bored, he acted cruel and mean to people just to have something to do. He acted like this was somehow perfectly justifiable and that there was nothing wrong with it whatsoever.
Understand that sociopaths/psychopaths are often bored. One way to get out of boredom is to be cruel to someone. This will create a lot of tension and drama in the air and will tend to cause a scene. To this type of person, an ugly scene is better than being bored.