Complexity is easy; simplicity is hard.

The scientific study of behavior must be based on objective, measurable data.

"Every book should be a conversation between the author and the reader."

Act as if what you do makes a difference. It does.

释义：脸上没有愤怒的表情是对他人的尊重，嘴里不说愤怒的话会散发出美好的气息。心中没有愤怒是无价的宝藏，这种心态是永恒不变的真理。

No man, for any considerable period, can wear one face to himself and another to the multitude, without finally getting bewildered as to which may be the true.