Who died and made you worldpolice?

Some people are always prone to interfere. My question is now: why? Why do they want to make the life miserable for others? What do they get out of it? Is it just the fact that their life is so miserable they want others to have a horrible time too? Or is it just in their genes? I don't understand. Why bother? Isn't it better to pick your battles and interfere when it is necessary, I mean if someone or something gets hurt or whatever. That's a fantastic time to interfere. We need more of that. The interferers I'm talking about are the ones doing it only to assert themselves, I think. There's no other gain. There can't be.