Ad copy is not usually so great that it can become a 'quotable quote' but this one by Nike is simply superb. Not sure which advertising company has come up with this quote, but it really is quite beautiful. It's something that will connect to every individual at some point of their lives or the other. Here is the full quote.
"All your life you are told the things you cannot do. All your life they will say you're not good enough or strong enough or talented enough; they will say you're the wrong height or the wrong weight or the wrong type to play this or be this or achieve this. THEY WILL TELL YOU NO, a thousand times no, until all the no's become meaningless. All your life they will tell you no, quite firmly and very quickly.
AND YOU WILL TELL THEM YES."