I've faced this problem for almost every task in my life, from the creative stuff already mentioned too less obvious things, like socializing (Seeing what you said wrong without knowing how you could have said it better). Because of this, the only things I have been able to bear "practicing" are ones that are outside of any public view. Ones were my taste was nonexistent. Code is one of them. We don't see much code (good or bad) in public, and so it's one of few areas where my taste could only improve after I saw the failures in my own work after I had produced it, rather than during.