1. Highlighting Guan Yu's heroism and loyalty: Through Yuan Shu's contempt, it is highlighted that Guan Yu's status is not high, but he is extremely brave, thus strengthening Guan Yu's image.
2. Reflect the social hierarchy at that time: The Three Kingdoms period was a hierarchical society, and a person's position often determined his position and influence in society. Yuan Shu's contempt also reflects the influence of this social hierarchy in the war.
3. Reveal Yuan Shu's pride and underestimation: Yuan Shu's contempt also reflects his pride and underestimation, which is one of the reasons for his failure.
4. Predict the rise of Guan Yu: Yuan Shu's contempt also indicates Guan Yu's bravery and loyalty. Despite his humble position, he will gain more recognition and respect, implying his future rise.
In a word, through this description, the author not only highlights the image of Guan Yu, but also reflects the social environment and character at that time, paving the way for the development of the story.