Remember MAD magazine's feature of the same name?

I just thought we could start some suggestions since we hear the same silly stuff over and over.

My mom works in drugstore and this woman came in exclaiming she had to go on a diet. Mom suggested that Women's Day had started a low carb recipe section, and the woman exclaimed, "Oh, I'm not going on THAT. I don't believe that man hit his head, it was his diet that killed him!"

My mom just backed off at that point, but I said the next time this happens, she can mention, "Yes, he was over seventy and still playing tennis."

Any one else have a story with a suggested snappy comeback? Like mine, it could be something you thought of after the fact!