Eliezer Yudkowsky said this quote

You can only arrive at mastery by practicing the techniques you have learned, facing challenges and apprehending them, using to the fullest the tools you have been taught, until they shatter in your hands and you are left in the midst of wreckage absolute... I cannot create masters. I have never known how to create masters. Go, then, and fail... You have been shaped into something that may emerge from the wreckage, determined to remake your Art. I cannot create masters, but if you had not been taught, your chances would be less. The higher road begins after the Art seems to fail you; though the reality will be that it was you who failed your Art.