The human animal, like others, is adapted to a certain amount of struggle for life, and when by means of great wealth homo sapiens can gratify all his whims without effort, the mere absence of effort from his life removes an essential ingredient of happiness. The man who acquires easily things for which he feels only a very moderate desire concludes that the attainment of desire does not bring happiness. If he is of a philosophic disposition, he concludes that human life is essentially wretched, since the man who has all he wants is still unhappy. He forgets that to be without some of the things you want is an indispensable part of happiness. —Bertrand Russell, The Conquest of Happiness