There is a pretty good article in the latest Harvard Business Review called "Manage Your Energy, Not Your Time". When I read it a light bulb went off about why I feel great if I have given a lot of feedback on a given day. There is a connection.
Basically the article talks about different influencers to your energy level. In the section where they talk about Emotional energy, they have this quote: "A powerful ritual that fuels positive emotions is expressing appreciation to others, a practice that seems to be as beneficial to the giver as to the receiver."
I know this falls into the "big duh" category, but I thought it was an angle worth highlighting. I did not recall M&M highlighting the positive impact on yourself when you give feedback. I would think most folks probably get this "boost" when they give someone some affirming feedback.
Thanks to M&M's recommendation, I now subscribe to HBR (and love it!). However, you can get this article for free at www.HBR.org.