The most important thing in mathematics is to understand the concepts, not just to memorize the formulas.
To live is the rarest thing in the world. Most people exist, that is all.
The most important thing is to focus on the user and all else will follow.
The walls of a garden should be high enough to keep the world out, but low enough to let the sky in.
2009年：贝索斯致股东信《执着于用户体验》
