Once you amass a certain amount of wealth, the social circles you keep change, and thus your expectations do too. That's the problem.
For me, $150 million would be an absurd amount of money. For Lewis, the folks that he associates with now are often quite above that level, so the boats and planes and homes they own make the lifestyle that he can enjoy with 150 million seem less extravagant. You get recalibrated when hanging out with the new crowd, and the problem is, there's always a bigger fish.
Even at the multi-billionaire level; supposedly Paul Allen and Larry Ellison got into a pissing match with their boats, which led to Pauls "Octopus", which is clearly more boat than anyone needs.
http://en.wikipedia.org/wiki/Octopus_%28yacht%29
It stopped being about the boat itself, and became about beating the other guy's boat.
I've seen many happiness studies which prove time and time again that
absolute wealth is not the key to happiness;
relative wealth is. Human nature is what it is, and will not be denied. If you are the wealthiest person in your social circle, you probably will be happier than if you are in the bottom half of wealth in your social circle, even if example 1 is 100K per year, and example 2 is 1 million per year.