No person has the power to have everything they want, but it is in their power not to want what they don't have, and to cheerfully put to good use what they do have.
-- Seneca, Moral Letters, 123.3
John D. Rockefeller, who was as rich as they come, believed that "a man's wealth must be determined by the relation of his desires and expenditures to his income. If he feels rich on $10 and has everything he desires, he really is rich."....Today, you could try to increase your wealth, or you could take a shortcut and just want less.
* Source: The Daily Stoic by Ryan Holiday and Stephen Hanselman