It's interesting that you think that people who are really driven can end up being unsatisfied because of that nagging feeling they have telling them there's more to be done.

I would think that having a lot of money would give you the freedom to choose your work, and the ability to wake up every day and work on something you feel passionate about would make you happier. I guess you could say that you don't need a lot of money to do that. But it would make it easier.