" Notice the difference from the earlier equations? All of the evolutionary and biological formulas focus us on the numerator of our haves. If you are unsatisfied in life, that’s what you most likely have been doing all these years. But that ignores the denominator of the equation—the wants. As you increase your haves without managing your wants, your wants will proliferate and sprawl. You can easily be less and less satisfied as you move up the success ladder, because your wants will always outstrip your haves. And when they do, your satisfaction will fall. "

― Arthur C. Brooks , From Strength to Strength: Finding Success, Happiness, and Deep Purpose in the Second Half of Life