:) It's not rational. You should try to get in one. There's a site called HiGear that will let you drive a Roadster for $500 a day. It's steep, and you only get about 100 miles, but it's an experience that words can't fully describe.
Rationality is about how to achieve what you want, not about what you should want. If it makes you happy, and you believe that it will continue to make you happy enough that you're willing to pay for it, then that is rational.