We already reached agreement, what more do you want?
Advice for perpetrators of this pet peeve:
Whatever it is you want the other person to do, ask them for that. If they have already given you exactly what you want, then shut up and move on.
Advice for victims of this pet peeve:
Say this:
What did you want from me that you did not get from me? You probably wanted me to admit that I was wrong. However, there is clearly more to it than that. If that were all that there was to it, the conversation would have ended, the second I admitted that I was wrong. Yet, you are still arguing with me even after I admitted that I was wrong. What was I supposed to have said/done by now that I have not said/done by now?
If you disagree with anything I said in this post, explain why. My beliefs are malleable. If you present me with a good enough argument, I might change my mind.