Yeah, I know what you're talking about... me and my dad never could get along either. Now that I've moved out, our relationship has somewhat improved though (we're not exactly friends, but we can get along now). Since you have already moved out, that's not an option for you though.
My advice will be a little different from the other advices given so far. If you really can't get along with your parents, why visit them? Nobody's forcing you to go.
You can tell them you're oh so sorry and blah blah blah, but that doesn't solve the problem. They will still annoy you, and it's just a matter of time before it gets out of hand. You can tell them what you don't like about them, but chances are they either don't want to change or are unable to.
If you still want to keep visiting them, I'd say keep strict lines. Make clear that once one of your parents crosses that line, you're gone. Don't go shouting or name-calling, but when they are abusive/intolerant again, just walk out the door. You don't have to take what they do to you.
I have been through all of this as well, and for me the solution was to see my parents less often. It did take some time though. It only recently improved, after about a year of living on my own. During this period I visited them once a week. I don't know how much you see them, but if it's often enough for them to make you angry, it's too often.
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