Designer Milton Glaser is featured in the video series from Berghs College of Communication's 2011 Exhibition. It's really an amazing talk that you must watch in full.
Says Glaser, "Understanding development comes from failure. People begin to get better when they fail. They move towards failure, they discover something as a result of failing. They fail again; they discover something else. They fail again; they discover something else. So, the model for personal development is antithetical to the model for professional success [which is based on repeated demonstration of expertise]."
And: "The real embarrassment about failure is that you learn you are not as good as you thought you were." Nevertheless, "you must embrace failure, you must admit what is, you must find out what you're capable of doing, and what you're not capable of doing."
More information on the Berghs Exhibition here.