With calculation and strategy, why did Guan Yu's head directly scare Cao?

The reason why Guan Yu's head scared Cao Cao was very simple, because Guan Yu's head had become a hot potato at that time. You see Guan Yu is Liu Bei's sworn brother, so Liu Bei must be his sworn brother's body. As an enemy of Liu Bei, Cao Cao, if Liu Bei wants Guan Yu's head back, he can only fight to get it back. This means that it is not cost-effective for Cao Cao to beat Liu Bei, who is eager to avenge his brother. After all, Xiang Yu was not directly killed by Cao Cao.

Therefore, Cao Cao carried such a big pot for Wu Dong, and Cao Cao was very reluctant. This is why Cao Cao felt very troublesome when he saw Guan Yu's head, and he was even scared silly. But Cao Cao is Cao Cao after all, which is not comparable to ordinary people's calculations. Shortly after Cao Cao got Guan Yu's head, he immediately asked the carpenter to carve a body with incense and put it together with Guan Yu's head.

Cao Cao personally led the civil and military officials in the DPRK to bury Guan Yu as a vassal. Even Cao Cao did not hesitate to worship Guan Yu's spirit in his personal capacity. In addition, he posthumously awarded Guan Yu as King Jing, and assigned special personnel to guard Guan Yu's mausoleum. This kind of funeral is unprecedented for Cao Cao. Cao Cao's courtesy and respect for Guan Yu made the whole world applaud Cao Cao. But Cao Cao only told the world that Yunchang Huarong gave me a break, and today I can only repay him with this!

After learning what Cao Cao had done, Liu Bei no longer hated Cao Cao, but only Wu Dong's treachery. Immediately, Liu Bei issued an order to the whole country of Shu, demanding that the whole country prepare for war and prepare to attack Dongwu to avenge Guan Yu. Wei also avoided an unnecessary war, so it seems that Cao Cao is indeed a lean man. How can he not be admired for his means and scheming?