At first glance, it seems hard to find anything positive in the phenomenon of envy. Someone else has something you don’t—a possession, a skill, a character trait, a relationship, a lifestyle—and that makes you feel bad. You long to have what she has; you resent her for having it; you feel bad about yourself for lacking it. Surely none of that’s is great.

And it gets worse: envious feelings can lead to antisocial behavior. Maybe you’ll try to steal the object from her. Maybe you’ll try to bring her down to your level. It’s this antisocial component that makes envy not just a bad idea but a potentially immoral emotion; this, presumably, is what got it onto the list of the “seven deadly sins.”

If we wanted to pile on, we could add that envy combines with consumerism to produce a menace to the planet. Your neighbor buys a brand new phone, so you buy one too, regardless of the fact that you don’t really need one. You’ve got a fancy new toy, but at the cost of the resources it’s made of and the fossil fuels it took to produce it and ship it.

Demoralizing, antisocial, and planet-destroying: envy’s got a lot to answer for.

If all this is true, then maybe I’d be better off admiring people rather than envying them. I myself would be happier, and they’d be safe from glowering glances and hockey sticks coming from my direction.

But Sara Protasi, our guest this week, makes a really interesting case for the defense. While she acknowledges that there are destructive kinds of envy out there, she points out that there’s also a good kind—one that motivates us to raise our game. Think of a pair of tennis partners. (Let’s call them Venus and Serena.) Imagine that Venus has a great backhand shot and Serena has a great serve. Serena will envy Venus her backhand shot and will strive to improve that aspect of her game; Venus, meanwhile, will envy Serena her serve and will strive to get better at that. They both improve, they keep themselves in peak condition, and they stay friends. What’s not to like?

In short, maybe healthy rivalries are good for us—and maybe envy is their indispensable condition. Without the painful sting of envy, would we really work so hard to develop that killer serve?