An educated youth that knows it all is hopeless. A good idea never was lost. From his neck up, he is worth anything that his brain can produce. Opportunity is missed by most people because it is dressed in overalls and looks like work. The greatest of all studies is human nature.
Fools call wise men fools.
A wise man never calls any man a fool. There's a better way to do it. The world owes nothing to any man, but every man owes something to the world.