Read Gary Foreman's blog entry titled "A Puzzle", and then you tell me...
I think "rational" is in the eye of the beholder. I sometimes spend more money than I need to, or really want to, but I can rationalize it away. For instance, I need to get my eyes checked and will need new glasses. I know there is an optometrist that only takes walk-ins, so I could go and maybe get right in, but maybe have to wait awhile. She's cheap but she's good and I could save money by going there.
What do I do? I go to an optometrist where I can set an appointment and be guaranteed to have that specific time. It costs almost 25% more. I can rationalize that by saying that I would probably waste time sitting in the cheaper optometrist's office, but in reality my time is not worth that much, especially if I'm not doing anything, anyway. I could read a book while I wait at the other optometrist's, or make lists or daydream or whatever... but no, I gotta pay through the nose, rush in, rush out and go home and read a book.
Makes a lot of sense, doesn't it?