Two old acquaintances, who hadn't seen each other for years, were walking down the street together, renewing old times. "Just a minute," said one, "I think I hear something," and turning a loose paving stone over he liberated a cricket which was chirping merrily away.
"Why, that's astounding. Of all the people on the street at this hour, hurrying from work, you alone hear the cricket above all the traffic noises." "My friend," said the first. "I learned a long time ago that people hear in life only what they want to hear. Now, the noise of traffic has neither increased nor decreased in the past few moments, but watch."
And as he finished speaking he let a silver half dollar fall from his pocket to the sidewalk. Everyone within an amazingly large hearing distance stopped and looked around.