A person from Zheng State who wants to buy shoes first measured his feet and put the measured size on his seat. When he arrived at the market, he took a fancy to a pair of shoes, but found that he had forgotten to bring the measured size. So hurriedly ran back to get it. When he returned to the bazaar, the bazaar was already gone, so no shoes were bought. Someone asked him: "Why don't you try it with your own feet?" The man said, "I would rather believe in the size than your own feet.