“Professional activity is a source of special satisfaction if it is a freely chosen one -- if, that is to say, by means of sublimation, it makes possible the use of existing inclinations, of persisting or constitutionally reinforced instinctual impulses. And yet, as a path to happiness, work is not highly prized by men. They do not strive after it as they do after other possibilities of satisfaction. The great majority of people only work under the stress of necessity, and this natural human aversion to work raises most difficult social problems.”