The world owes all its onward impulses to men ill at ease; the happy man inevitably confines himself within ancient limits.

The only limit to our realization of tomorrow is our doubts of today.

Expertise in any domain involves the automation of basic skills, freeing attention for higher-level aspects of performance.

一句话，先是太胆小，明知错的事却不敢不做；后来也还是太胆小，明知对的事却不敢去做。