假设有效性的唯一相关检验是预测与经验的比较。

若心不专一就会一无所获，要想求全就学得不精，一心二用就会学不明白。意在强调专心致志和“术业有专攻”的重要性，只有专注于自己的志业，不好高骛远，才能有所成。

Your most unhappy customers are your greatest source of learning.

A good director is like a good conductor; he doesn't make a sound, but he makes the orchestra sound great.

Quality is not an act, it is a habit.