The gentleman thinks of virtue; the small man thinks of land. The gentleman thinks of law; the small man thinks of profit.

Huai De is someone who adheres to their own convictions and insists on acting according to them.

Huai Xing is someone who upholds moral principles and expects others to do the same.

Huai Tu is someone who easily blends into their environment, even if it's a bad one.

Huai Hui is someone who yields to personal gain, even when they know it's wrong.

There are four types of people in this world: the noble person (Junzi), the petty person (Xiaoren), the wretched person, and the in-between type.

A Junzi is like Jesus—you hold that what's right is right and what's wrong is wrong, regardless of the circumstances. If everyone else is wrong, you battle against the whole world until you're crucified. History will prove you were right.

A wretched person is like those in the TV series "Yongzheng Dynasty" who borrowed money from the state and then lent it out at usurious rates—they are essentially doing evil.

What kind of person is a Xiaoren? It's like the eldest top-scorer (Zhuangyuan) in "Yongzheng Dynasty." His colleagues all borrowed money from the national treasury, which was wrong. If he truly held to virtue and morality, he would righteously point it out, clash with his colleagues, and accept the outcome of being isolated—that would be a Junzi. But he didn't do that. Instead, he catered to the group and borrowed a single tael of silver, as if to say, "Look, I'm one of you." He's not a bad person; he's just shameless. He knows what's right, but he's unwilling to fight for it. He cherishes his reputation and is reluctant to sacrifice his own interests. He prefers everyone to get along harmoniously. This is what Confucius meant by the "good old boy"—a thief of virtue.

Many people can't achieve anything—they belong to none of the three types, an in-between sort. They lack the courage to be wretched, they're unwilling to pay the price to be noble, and they don't even understand how to properly be petty. So they live every day filled with envy, jealousy, and resentment—resentful that others aren't noble, jealous that others can be wretched.

This is mental friction.