The fountain of content must spring up in the mind, and they who have so little knowledge of human nature as to seek happiness by changing anything but their own dispositions will waste their lives in fruitless efforts.

The great secret that all old people share is that you really haven't changed in seventy or eighty years. Your body changes, but you don't change at all. And that, of course, causes great confusion.

韧性是通过克服挑战建立起来的。