Why did Cao laugh at Zhuge Liang after withdrawing from Chibi?

The landlord said that Zhang Fei, Zhao Yun and Guan Yu laughed three times when they were laughing?

The war can be defeated, but the momentum cannot be defeated. Trying to stabilize the morale of the army is not only a kind of personal self-comfort, but also a kind of group self-comfort. Of course, it is also a kind of calmness when frustrated, a kind of wind of competing with each other.