I did not realize I would open up such a fire storm with this question. I thank all of you for your great viewpoints. After reading this thread and re-reading the chapter twice over I think I have come to the conclusion that Mr. Darcy is mortified by the fact that he has had to re-examine his initial belief and admit he was mistaken re Elizabeth. But I also think he is equally mortified that he should be attracted to someone of a lower social status. Perhaps his social position expects more in a Darcy bride?

My review of that chapter also leads me to believe that he does not regret or even acknowledge his bad behavior at the Assembly.