I recently heard Tal Ben-Shahar on NPR's Diane Rehm show.
He wrote Happier: Learn the Secrets to Daily Joy and Lasting Fulfillment
Tal teaches "Positive Psychology," one of the most popular courses at Harvard University. From the show, I gathered one bottom line was to try not to do too much: simplify. You can see how this might apply to Harvard students.
I suspect this applies to many of us who are looking for magic bullets to solve our GTD issues. Here are a few links:
Tal's website
Link to the Diane Rehm show where you can listen to the broadcast
Link to an NPR All Things Considered segment
Google of Tal Ben-Shahar
The book at Amazon
The book at 43 Folders bookstore (though I've found no mention of the book anywhere else on the 43 Folders site)