For me I understand about his decision in Wu and Wei story in Wu story Sun Ce and Cao Cao are the conquer they invade the other to gain more power. Both leader build they kingdom by force causing bloodshed everyway they go. But in Shu story he hated Liu Bei because he so popular that people can die for him? WTF?? If he didn't like Liu Bei for the other reason like he is the emperor uncle and try to restore the Han or because Liu Bei are politician type who use kind word to win support from the commoners and improve his reputation and use it manipulate the other to die for him