The writer Walker Percy, one of the so-called Southern Stoics, would ask and answer that question. “Jealousy,” he said, “is an alteration in the very shape of time itself. Time loses its structure. Time stretches out.” Because we become so consumed, we lose the ability to think of anything else. Our chest tightens and every other track in our mind stops but this one.
The Stoics held that there were four passions that contributed to our misery: Distress, Fear, Lust, Delight. It seems like envy and jealousy could fit in either of the first three categories, but in fact the Stoics put it under Distress. Close enough because the irrationalness of jealousy—wanting what someone else has, feeling slighted by the success of another person—is distressful. It’s also painful (Joseph Epstein once quipped that of all the sins, envy is the only one that isn’t any fun).
The question then is why do we give so much of our lives over to it? Why, if we’re not careful, can we waste enormous chunks of today being miserable over the fact that so-and-so is doing well or how badly we feel we deserve what so-and-so is enjoying? Because jealousy is a blinding passion. As Percy said, it consumes us and twists our logic until nothing but itself makes sense.
So if you want to know what envy is, here’s your answer: It’s insanity. It’s death. It’s a thing to be avoided at all costs.