Rminds me of a time when I needed to get a ticket back from Europe for a certain relative (I was forced into it, as she was stuck). She said, "well, its not costing you anything, it only miles."

To which I said, "no, the ticket is only $299, why would I use miles, are you crazy, the miles would cost me at least three times as much!"

I then went on to explain that if she had not been so stupid and have given all her miles away to everyone and her brother when she had a ton of them in previous years, that she would not have to be sponging off me now.

I bought the ticket and we have not spoken much since.