“You can fool everyone else, but you can't fool your own mind.”
“You can't fool Mother Nature, and you can't fool market forces (at least not for long)”
“Life's no piece of cake, mind you, but the recipe's my own to fool with.”
“If you once forfeit the confidence of your fellow citizens, you can never regain their respect and esteem. It is true that you may fool all of the people some of the time; you can even fool some of the people all of the time; but you can't fool all of the people all of the time. -Speech at Clinton, Illinois, September 8, 1854.”
“Only fools and dead men don't change their minds. Fools won't and dead men can't.”
“Any fool can make a ruleAnd any fool will mind it.”