He died suddenly from overwork in his previous life.
After rebirth, Cheng Shang: I will quit doing whatever I love.
Yi Zai: What? Is Cheng Shang, the book king, quitting? Then I won't do it either.
The second-generation ancestors of City A: Dad, you see, Cheng Shang doesn't work anymore, and neither do we!
Purpose: cherish the present moment