Guo Jia is a clever counselor, with amazing thinking ability, first-class strategy and judgment, and he is happy to be attributed to Cao Cao, who is good at identifying heroes. Guo Jia is loyal to Cao Cao. Since he left Yuan Shao's office, he has been Cao Cao's counselor. Guo Jia's greatest contribution to Cao Cao was the war with Yuan Shao, and he could win with fewer enemies and more. Let Cao Cao rule out his suspicion and become Cao Cao's confidant. Guo Jia's contribution in history is obvious to all, and his great contribution to Cao Cao reflects his great strategic talent.
At that time, Liu Bei was still the defeated soldier under Cao Cao. Guo Jia suggested that Liu Bei should not be released or executed. The execution will arouse the dissatisfaction of heroes all over the world, hoping to put him under house arrest for life. But Cao Cao had his own career at that time and didn't care much about Guo Jia's suggestion. Coupled with Liu Bei's high emotional intelligence, Cao Cao did not feel Liu Bei's ambition at all, thinking that Liu Bei recognized the reality of the law of the jungle and let him go.
Guo Jia worried about Sima Yi before he died, which shows how serious it was for Guo Jia, Cao Cao and the country. Accustomed to a high position, Cao Cao has stopped listening to other people's suggestions. Coupled with Cao Cao's high heart, Guo Jia just tried his best to defend the country, but Cao Cao could not understand the thoughts of his wise men, and he did not think that he could be threatened by Sima Yi.