The key point is to learn to "control your own desires". Control your appetite and laziness, and naturally you won't get fat and greasy; Control your material desires, and you will naturally not compare with others and covet other people's things; Control your lust, flowers and plants all over the world can't disturb your heart. Even if you are bald and have wrinkles, what does it matter? It is enough to have a wife (husband) to grow old with you. Your heart has never been disturbed. You never want to flirt with anyone but your spouse. What does it matter if you are symmetrical or charming? I'm afraid many people have never had peace of mind and are never satisfied with what they have. When they reach middle age, they fantasize about flirting with young women (men) to prove that they are still young. If you can't control your surging heart, even if you learn all the ways to keep yourself from being "greasy", you are still a "greasy middle-aged man" in your bones, because your eyes are full of desire and your greasy nature has been exposed. Who do you want to show it to if you don't want to be greasy?
Zhuangzi said: "Man has no self-nature, God is useless, and saints are nameless." People who reach the highest level of moral cultivation have no selfish thoughts, and their spiritual world is completely free from the shackles of people who have no external resources, and their ideological cultivation is perfect, without the shackles of fame and fortune. When you really cultivate your self-cultivation to the point where "the world is famous but not remonstrated, and the world is not depressed", external interference can't interfere with your inner world at all, then you have reached the realm of "freedom". How can you be so greasy?