"More Than is Required"

 "Always do more than is required of you."

— George S. Patton

Popularity or Peace

 "Avoid popularity if you would have peace."

— Abraham Lincoln

"The Fastidious are Unfortunate"

 "The fastidious are unfortunate; nothing satisfies them."

— Jean de la Fontaine

"I Would Rather Try to Persuade"

 "I would rather try to persuade a man to go along, because once I have persuaded him he will stick.  If I scare him, he will stay just as long as he is scared, and then he is gone."

— Dwight Eisenhower

"The True Measure of a Man"

 "The true measure of a man is how he treats someone who can do him absolutely no good."

— Ann Landers

"Do Not Trust to the Cheering"

 "Do not trust to the cheering, for those persons would shout as much if you and I were going to be hanged."

— Claude M. Bristol

Wisdom through change and correction

 "He that never changes his opinions, never corrects his mistakes, will never be wiser on the morrow than he is today."

— Tryon Edwards

"Makes Himself Progressively Unnecessary"

 "A teacher is one who makes himself progressively unnecessary."

— Thomas Carruthers