“If Bob envies Alice, he derives unhappiness from the difference between Alice’s well-being and his own; the greater the difference, the more unhappy he is. Conversely, if Alice is proud of her superiority over Bob, she derives happiness not just from her own intrinsic well-being but also from the fact that it is higher than Bob’s. It is easy to show that, in a mathematical sense, pride and envy work in roughly the same way as sadism; they lead Alice and Bob to derive happiness purely from reducing each other’s well-being, because a reduction in Bob’s well-being increases Alice’s pride, while a reduction in Alice’s well-being reduces Bob’s envy.31 Jeffrey Sachs, the renowned development economist, once told me a story that illustrated the power of these kinds of preferences in people’s thinking. He was in Bangladesh soon after a major flood had devastated one region of the country. He was speaking to a farmer who had lost his house, his fields, all his animals, and one of his children. “I’m so sorry—you must be terribly sad,” Sachs ventured. “Not at all,” replied the farmer. “I’m pretty happy because my damned neighbor has lost his wife and all his children too!”