Mistakes, "failures", whatever you like to call them are all part of the road to success!
People told the Wright brothers they were mad to even try to make a heavier than air machine - where would we be if they had listened to the "dream stealers"?
Henry Ford said that failure was just an opportunity to begin again more intelligently!
Even the RAF motto "Per Ardua Ad Astra" comments that we may encounter difficulties on the way to the stars.
Kennedy said that we choose to go to the moon not because it is easy but because it is difficult.