We all have the crazy types who come to our sites and forums. Sometimes they are a burden and make running a site a chore, but there is hope. You can always ban those users who continue to act up. If I get a user who isn't agreeing to behave, I give them warnings, and if they keep it up, I just ban them. I'm not going to let a user be rude and obnoxious, break the rules and they stay after they apologize. Sometimes they apologize thinking it will help, but they usually always continue after.