Yeah, when you think you're good at something, you think you know how it ought to be done, and thus (likely) close your mind to other possibilities (because you already know the 'right way', and that means the other way must be wrong).

Zen Mind, Beginner's Mind is the book it's from. Very, very worth the read, and this coming from someone who thinks the whole new-age zen hippie thing and most books are BS (and they miss the point).

He has another book, but it isn't as good.