One of my favorite quotes

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 been 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 great enthusiasms, the great devotions, 
And spends himself in a worthy cause, 
Who at best knows achievement and who at 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.

- Theodore Roosevelt