There is no reason. Striving to be a good person is counter-productive on the spiritual path. You should strive to be yourself, be true to yourself. You will never get rid of your “badness”, you can only mask it by “working on” your “goodness”, and it will be inauthentic, fake. You need to accept and surrender to everything good about you and everything bad about you.

It doesn’t mean you have to act on your bad impulses. This is just stupid, most of the time, and it doesn’t serve you. For example, if someone “wronged” you so much you want to kill them, don’t think there’s something bad about that. Accept your hate and desire to do physical harm to them. But to actually go out and kill them? Well, if you really want to organize the whole thing, experience the emotional shock of killing a person, throw up, wallow in anxiety and guilt for years and almost suredly rot in prison for the rest of your life, be my guest. Sounds rational? Not really.

Most “bad” things we do are utterly irrational in the same way, it’s just hard to see it when we do it. Like getting angry at someone - irrational, most of the time. No one is better off. We just have no control over it because we suppress so much of it that at times it just breaks free and we wonder what happened.

So don’t suppress it. But don’t express it either. Allow yourself to feel this way, to have all these desires, accept all the evil in you. Just stay rational, don’t do anything in the passion of the moment. Stay alone if you need to and allow yourself to hate. It will subside, it always subsides. With time it will hold less and less power over you because it’s kinda boring hehe.