My two favorite quotes:
I do not think that there is any other quality so essential to success of any kind as the quality of perseverance. It overcomes almost everything, even nature.
John D. Rockefeller
Nothing in the world can take the place of persistence. Talent will not; nothing is more common than unsuccessful men with talent. Genius will not; unrewarded genius is almost a proverb. Education will not; the world is full of educated derelicts. Persistence and determination alone are omnipotent.
Calvin Coolidge
