Here's the real reason Zhao Yun left Gongsun Zan. Shortly after the burning of Luoyang, Liu Bei celebrated by doing the Dynasty Dance with the peach garden boys. Zhao Yun saw his sick moves and tried to join in. However, Liu Bei told him off for not wearing a green hat. Then Gongsun Zan ordered Zhao Yun to retreat. Zhao Yun threw his spear in anger and it impaled Hua Xiong. He really wanted to join the manly green hat men.