The shift of a mere apostrophe by a single letter can make all the difference.  We're referring here not to the "Editors' Choice" videos that are highlighted at the top right of this Web page—the favorite videos of Big Think staffers—but to the clips that piqued the interest and imagination of one staffer in particular, Paul Hoffman, our editorial chairman.  In compiling his 10 "must-watch" videos, he avoided duplicating any ones that were on our just-published list of the 10 most popular videos in 2009.  Not that Paul doesn't share your interest in health, wealth, and happiness, or your enthusiasm for Ricky Gervais and Stephen Fry. It's just that we caught him in a contemplative mood.  If you have a chance to put together a list of your own Big Think favorites, please share it with us.  Here, in no particular order, are Paul's choices: