If the poor man had a shirt

The general told the poor man about the king and asked him how much he could buy his shirt, but the poor man didn't want to trade it. Finally, the general traded his old cloak for this shirt. When he returned to the palace, he presented the shirt to the king. 
The prime minister saw that the shirt was old and worn. He said to the general discontentedly, "are you kidding?" the king also asked, "general, can you tell me why the original owner of this shirt is happy?" "Because he has everything he should have, and never expect what he can't have." the general said bluntly. "... never expect what he can't have." the king repeated the general's words. The prime minister turned pale and asked the general to blast out of the hall. But the king stopped him, laughed loudly and said, "good, general, you did a good job. I will reward you with a set of aluminum tableware. You must be tired. I'll send someone to take you back. You must be tired..." After the general left, the prime minister still stood in the hall and felt incredible. He didn't go back until the king came and patted him on the shoulder.