Since quitting my job a few months ago, I've been learning this lesson as a consultant. It turns out that to squeeze a mere 30 billable hours out of a week, I have to work about twice as hard as I ever had in a full-time job. And I was the most productive hacker in the company. Now I'm working much harder on projects that aren't always as cool, but it's worth it because it directly affects my livelihood and the customer's desire to continue working with me and recommend me to others.
IMO this is the only point that matters. Rich or not, we only value rewards that take effort. If your fairy grandmother showed up, waived her wand, and you suddenly had a couple billion, you wouldn't value it. If you work your a off to make a couple hundred K though, or to learn a new language, or learn to surf, etc. you will feel a great sense of accomplishment far more valuable than the coin.
I think that's by far the biggest stumbling block. Once there is a direct relationship between effort and reward most people behave appropriately and put forth a lot of effort. It also smooths over a lot of the lesser issues. Doing very boring things can be very exciting when doing it well results in big increases in reward. It becomes a high stakes game.