I think my dad is insane
How did he become insane?
Maybe from his upbringing from his mother. I don't know... but he is a crazy guy.
Your dad may have his issues, but calling him names like "crazy" and "insane" is rude. Don't judge your father, just love him.
Why should I? He's done nothing for me except giving me a shitty childhood.
I'm sorry your dad wasn't very kind to you, but how about trying to think in his perspective? Perhaps he could be sick and he doesn't realize or know, and you could be the one to love and help him out to get better.