A while back, the New York Times ran a interesting interview with Jim McCann, founder and CEO of 1-800Flowers.com . A lot of it was about the mistakes he made along the way, and how he rebounded. His conclusion:
"If you look at highly successful people, they make the same number of mistakes as others, but they recover quickly. They don’t sit around moaning about what they’ve done wrong."
As I've written, and teach in my workshops, there is no such thing as pure failure or pure success. Every failure has elements of success in it - at least you tried, and you probably learned something and accomplished something, even if you did fall short of your goal - and every success has elements of failure or compromise. Perfectionists and negative people don't see that: they think that anything that is not a huge success is an awful failure.
And dwelling on your failures is simply a waste of time.