badness doesn't come all at once. The dominoes fall over time. You hurt someone by mistake and they let you get away with it. Then you try hurting them on purpose, and they still stick around. And then you realize that the more you hurt them, the better you feel. So you keep hurting them, and they keep hanging on, and the years roll by and you convince yourself that the fact that they still stand by you means that the pain you cause is okay.