a little silver
One day a rich but miserly Hasid came to a Rabbi. The Rabbi led him to the window. "Look out there," he said, "and tell me what you see."
"People," answered the rich man.
Then the rabbi led him to a mirror, "What do you see now?" he asked.
"I see myself," answered the Hasid.
The Rabbi said, "Behold -- in the window there is glass and in the mirror there is glass. But the glass of the mirror is covered with a little silver, and no sooner is a little silver added than you cease to see others and see only yourself."