I heard an anecdote recently that has stuck with me: A Buddhist monk was taking a walk one night. It was very dark and he didn't have a lantern. As he walked, he stepped on something and felt it squish beneath his foot. It was too dark to see but he was sure he had stepped on a frog. This disturbed him greatly because he was a devout monk and took seriously the Buddhist precept of harming no creature. He returned to the monastery wracked with guilt. He tossed and turned all night, feeling awful that he had killed the frog--he even had a nightmare in which a crowd of frogs surrounded him and demanded his life in exchange. The next morning the monk arose early and when it was light he walked down the path to find the dead frog. Instead, he discovered that what he had stepped on was a rotten eggplant. And so he had subjected himself to a night of guilt and anxiety over something which, it turned out, had been an illusion of his own making.