Which is why some self-made billionaires still live like this:
Ikea founder Ingvar Kamprad insists on flying coach, takes the subway to work, drives a ten-year-old Volvo, and avoids suits of any kind. It has long been rumored in Sweden that when his self-discipline fails and he drinks an overpriced Coke out of a hotel minibar, he will go to a grocery store to buy a replacement. It's clear that this is a frugal man. But is he the richest man in the world? That's a matter of some debate.
It amazes me how many of the truly wealthy are eccentric. I wonder if it is a correlation or a causation thing.