"People are miserable and don't know how to be satisfied. When they get Long, they hope to get Shu." This proverb means that people are miserable because they never know how to be satisfied. When they get Long, they want to get Shu. A metaphor for greed?

This should not be called a proverb, but a famous quote. The original words were spoken by Liu Xiu, Emperor Guangwu of the Han Dynasty, to Cen Peng. The original intention was to be proactive. Encourage Cen Peng; later Cen Guo really captured Shu, and finally Liu Xiu unified the world and established the Eastern Han Dynasty. The meaning of this sentence gradually changed until Cao Cao quoted it in the late Eastern Han Dynasty.

When the girl you talk about uses this sentence, she should be positive and aggressive, not satisfied, rather than greedy.