If you don't like something about yourself, or feel that you are being problematic in relationships, you can change. It's called personal growth. You can't change anyone else, but you can change yourself. Try therapy. Try googling things. Example: if you're always arguing with someone, say, a particular person, and you find yourself being particularly hurtful in these heated exchanges, google "how to have a productive argument," or "'non-violent communication." Play around with the wording. You can also read self help books. And post here.

In terms of not feeling guilty, well, the fact that you feel guilty, means that you care and wish things were different. That's a good thing. Maybe learn more about self compassion / self kindness, and self forgiveness.