When I was a kid, I was often ravaged by poison ivy. The key to poison ivy, once you have it, is not to scratch. Restraining yourself is hard, for your skin itches and you want relief. But scratching only makes poison ivy worse.

Avarice works the same way. We get infected, and we want to scratch, although we know we shouldn't do so. Possessing more and more promises relief, but only makes the situation worse. We keep scr…