Why are people such assholes?

And what makes manners?
There are people with horrible life stories yet they're still nice, not assholes just because their life wasn't happy.

@friendzonedgirl This is true. I was more or less projecting myself with that statement. It is a mistake to say that everybody is without their own special intricacies.

Yes, that's true. It should be something as they're coping with their problems and incapable to solve them they become frustrated and trust no one.
But I still don't see that to be a reason to be an asshole. We all have problems