For me, "you can't fake sweat" represents something bigger than just working out. It's more of a philosophy for life -- the notion that you have to put in the work to get the results. But staying motivated can be tough. Dan Pink gave a talk called "The Puzzle of Motivation" a few years back, and it has nothing to do with physical fitness per se, but it a fascinating exploration into what motivates us. I wanted to share it with you.