Warren Buffett, the American investor and the richest man on this planet, off and on recently said, "I don't hold myself to a standard of perfection, or I would have committed suicide a long time ago."
That gives us the point that nobody is perfect and perhaps one can only aspire to be perfect. No doubt, it is a good idea to try for perfection, but one must know the art of compromise.
As they say, life itself is a great compromise. To remain in sanity, the essential message that Buffett gives us to realize that one can't be always the winning horse. Accept and analyze your failures so that the next bid becomes a shade easier. Realize that you have to emerge stronger after a failure. Only then one can hope to carry on without falling a prey to frustration and depression as a result of not attaining perfection.
Big goals come with big risks and only the fearless and visionary can surmount the obstacles. One must realize that success is not perfection; it has its own pangs and might drag you further down. There is always a possibility of many failings in one's success. That is why T S Eliot had said, "Success is always relative, it is what we can make of the mess we have made of things."
Do what you can best, but never get into a 'mood swing' if things don't go as you had planned. You will always get a second chance and more. Keep in mind what William James had said, "The art of being wise is the art of knowing what to overlook."
Your success is measured in your ability come out of failures and turns them into success. If you fail, at times, it need not be because of your shortcomings; there are always several external factors working for or against you.