There once lived a man from Zheng who was about to buy some shoes. He had measured his feet beforehand, and placed the measurements on a chair. When it came time for him to go to the market, he forgot to bring the measurements with him. He had already picked out the shoes that he wanted, and then said, "I forgot to bring the measurements, I need to go home and get them." He returned home (to get the measurements, but by the time he got back) the market was closed, so he could not get the shoes. People would ask him, "Why did you not just try on the shoes?" To this he replied, "I would rather believe the measurements, I don't trust myself."