I think people are basically good and learn to be bad. Look at little children. They will come up to you and say "I love you" just because they can. Then when they get older they learn not to say it anymore, except to family members. At some point it's considered odd say "I love you" to someone you're not having sex with or related to.

I know a man who's a bully. But he takes in farm animals that are past their prime, and cares for them. Yesterday he had to put down a mule that he was very fond of, and he was clearly distressed. So while he's a jerk and a bully on the surface, he has some love in his heart.

I think we are born with innately loving hearts, and as we get older, that love gets stifled by rules and conventions and what have you. Then you have the choice to either find the love in your heart, or forget about it and become bitter.