Youth is fleeting, and beauty is old, which means that time will pass quickly, and a beautiful face will easily age, and it is no longer the beauty of youth. When the prosperity is exhausted, return to the original. It means that after you have experienced a lot of prosperity, everything will eventually return to dullness, and dullness is the true meaning of life.
This is mainly an expression, a feeling for the loss of time, and a return to the mentality after future prosperity. I realized that a person can finally face life calmly and feel the truest form of life. That's when a person grows up and finds his own state.