I agree with you there. If I feel that someone has completely misunderstood me as a person, or my motives, or has misrepresented me, then my reaction is purely to go apeshit rather than to feel offended. But if I feel that they are right, then I think whatever they said to offend me would be on my mind until I tried to make that comment inapplicable to me anymore.I hesitate to say I'm never offended, but it's definitely difficult to offend me. If someone says something about me that is negative, it doesn't bother me because I don't agree with it. I'm very secure and quietly confident in who I am, so I feel like I've nothing to "hide" or that could attract insults, accidental or otherwise. Before I was so secure with who I am though, it was a little easier to offend me. I think it all comes down to whether or not the person at the receiving end of the insult believes it, or cares if the person saying it is clearly mistaken or just being spiteful. None of it bothers me because I don't see an ounce of truth in insults directed towards me, and accidental ones just make me feel sorry for the clueless person saying them.
I believe it's all a matter of self esteem.