There's a Ask HN thread, maybe a few, of people who hit it rich and later lost it. The common theme is it's easier to make lots of money than it is to keep it, which is a little unintuitive.
1. Bad budgeting or lack of diversification. "95% of my money was in Enron"
2. Confirmation Bias. "I build a successful company once, I can do it again, but this time with my own money"
3. Hedonic Treadmill. "Flying commercial is so annoying, I'm going to fly private, and figure out how to pay for it later"
The good stories are around the middle.