Without a doubt, a life can never be complete without failure.
Of those that are the most successful, one will find with proper research that they have experienced the most failure as well.
The difference: the worlds most successful see failure as a chance to try again. Instead of remaining defeated, persisitance carries them forward.
Part of the belief system which backs this action from achievers, is that failures are merely learning opportunities in disguise. Without a doubt, ask any of these action-oriented individuals about their largest failures, and after describing the event they will make clear the learning opportunity which arose from it.
One may find great strength from accepting failure for what it is: an opportunity to learn and improve.