When a man feels inadequate to the work he has to do, he feels a general discontent which is exceedingly liable to take the form of envy towards those whose work is less exacting. One of the ways of diminishing envy, therefore, is to diminish fatigue. But by far the most important thing is to secure a life which is satisfying to instinct.
Source: The Conquest of Happiness, 1930, chap.6: Envy<
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