I like this, from 'The Art of Doing Science and Engineering' by Richard Hamming "with apparently only one life to live on this earth, you ought to try to make

I like this, from 'The Art of Doing Science and Engineering' by Richard Hamming "with apparently only one life to live on this earth, you ought to try to make significant contributions to humanity rather than just get along through life comfortably - that the life of trying to achieve excellence in some area is in itself a worthy goal for your life. It has often been observed that true gain is in the struggle and not in the achievement- a life without a struggle on your part to make yourself excellent is hardly a life worth living."