Your most unhappy customers are your greatest source of learning.

理智是不朽的，其他一切都是有限的。

关于我们所有人的基本事实是，我们活了一段时间，但很快就会死去。这个事实是我们所有愤怒和痛苦的根本原因。

The idea that we will make a society where literally everybody is graded, the good at the top, bad at the bottom, exactly done as it should be, is impossible. There are simply too many random factors: accidents, accidents of birth, accidents of things dropping on people's heads, illnesses, etc. We will never get to grade them, never get to grade people as they should.