There is no man, however wise, who has not at some period of his youth said things, or lived in a way the consciousness of which is so unpleasant to him in later life that he would gladly, if he could, expunge it from his memory.

你越了解自己，对你在别人身上看到的东西就越有耐心。

工具变量的美妙之处在于它们让我们以新的视角看世界。

The day you stop learning is the day you stop growing.