难得糊涂

聪明难
糊涂难
由聪明变糊涂更难
难得糊涂

郑板桥的难得糊涂
或多或少地
被现代经济学接受

When the cost of acquiring information is greater than the benefits to be derived from the information, it is rational to be ignorant. This is the economic theory of rational ignorance.

http://en.wikipedia.org/wiki/Rational_ignorance