Al Franken:
Mistakes are a part of being human. Appreciate your mistakes for what they are: precious life lessons that can only be learned the hard way. Unless it's a fatal mistake, which, at least, others can learn from.
John Powell:
The only real mistake is the one from which we learn nothing.
Richard Needham:
Strong people make as many mistakes as weak people. Difference is that strong people admit their mistakes, laugh at them, learn from them. That is how they become strong.
Theodore Roosevelt:
It is not the critic who counts, not the man who points out how the strong man stumbled, or where the doer of deeds could have done better. The credit belongs to the man who is actually in the arena, whose face is marred by dust and sweat and blood, who strives valiantly, who errs and comes short again and again, who knows the great enthusiasms, the great devotions, and spends himself in a worthy cause, who at best knows achievement and who at the worst if he fails at least fails while daring greatly so that his place shall never be with those cold and timid souls who know neither victory nor defeat.
From a speech given in Paris at the Sorbonne in 1910
Virginia Satir:
Feelings of worth can flourish only in an atmosphere where individual differences are appreciated, mistakes are tolerated, communication is open, and rules are flexible -- the kind of atmosphere that is found in a nurturing family.