I have one friend who likes to gamble. I've tried the old math argument with him and he dismisses it out-of-hand. He says that, yes, he knows it's a negative sum game but sometimes he wins and that makes it worth it. Then he says, "You spend money on a symphony or an art museum or an expensive restaurant, right? Those are guaranteed to leave you a little bit poorer at the end of the night. Same thing as gambling, but with a bigger guarantee."
And I didn't have a response.