Under the early summer night sky, Wang Qi spoke softly, "According to Su Junyu, I only know my joy but not the joy of my joy."
The so-called "joy" is just an emotion, something that everyone has. The pleasure of eating well, wearing comfortable clothes, making money, marrying and having children—all of these are forms of happiness.
"To know the joy of one's joy" means understanding why one is happy and what makes one happy.
Not everyone understands this level of self-awareness.
Some people think they crave fame and fortune, yet when they attain it, they feel a profound emptiness and lament with phrases like "In the next life, I will not be born into an emperor's family," thus negating their entire lives.
If such individuals with these mentalities attained longevity, I fear either the world would just have another soul stealing life in a shell, or they would be unable to withstand the torment of immortality, leading to madness, deep slumber, or self-destruction.