I wonder how many times Chesley Sullenberger had to break a simulated plane in half before he could land a real one in the Hudson River.
When things went wrong, he didn't lose his cool or panic. He was ready for things to go wrong even if he wasn't expecting it.
By failing all of the time during training, he conditioned himself to not be upset about failure.
I think that we improve continuously from failure into something that looks more and more like success. Success is very relative to what you are able to accomplish at a time. If failing teach you something, might be it's a success ?