I think I am a horrible human being.
Wow, Why do you feel this way?
I've done a lot of terrible things in my life.
If you are a horrible person then you need to do something to change yourself. Start taking concrete steps towards improving yourself as a human being.
I'm a bad person and will remain a bad person.
You can at least try to do a good thing. Like offering to help someone pick something up if they drop it. Start with simple things.