Some folks are slow to learn. I taught and took communication classes for most of 1997 - 2009 and it was not until 2011 that I learned about this powerful communication tool. (One elderly Cambridge Rhetoric professor wrote that it was the most important thing he had learned about communication during his long life!) I finally read about it in a textbook while substitute teaching at a local university and since then I've seen how effective it is.
You already know about feedback. How do you feel when someone says, "Hey, I'd like to give you some feedback on that talk/project report/whatever." I always brace myself inside; I know feedback is good for me, but not always fun to swallow.
Of course right after writing the above, a colleague emailed me especially to ask my feedback on a training class he taught. Apparently, Matt is more courageous than I. "How else can I get better?" he asks. But there is performance-driving communication form even more powerful than feedback.