Success comes from understanding your customers better than they understand themselves.

The greatest obstacle to being heroic is the doubt whether one may not be going to prove one's self a fool; the truest heroism is to resist the doubt; and the profoundest wisdom, to know when it ought to be resisted, and when it be obeyed.

You must not think that what is hard for you to master is humanly impossible； and if it is humanly possible， consider it to be within your reach.