The amateur pianist who took half a dozen years of lessons when he was a teenager but who for the past thirty years has been playing the same set of songs in exactly the same way over and over again may have accumulated ten thousand hours of “practice” during that time, but he is no better at playing the piano than he was thirty years ago. Indeed, he’s probably gotten worse.
Mere 10,000 hours of practice does not make you perfect. It probably makes you worse
