All bad things are interconnected, and any one of them is liable to be the cause of any other; more particularly fatigue is a very frequent cause of envy. ... 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, by Bertrand Russell.
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