The worst are the moronic well-meaning f***wits who will sit there and *insist* that you go first no matter how much you protest
+10000. So, like Cooker, I think this is one of the most effective ways to deal with it...
Now I often just put my eyes down and wait patiently till they give up on trying to wave me through.
I don't play that "you wave-I wave-you wave then neither one of us knows whether to go or not" game anymore. Plus, I don't like being told to go, and then feeling obligated to quickly move through the intersection to continue the politeness. They should go first, it takes less effort for them.