To be quite honest, I do think that any form of encouragement is positive and acceptable when it comes to making people move. It should be fun, though. The other day I bought a women's mag - their idea of working out and being healthy included following the latest trends from Hollywood (such as soulful indoor cycling - wtf?) and eating an almond or two whenever the sugar rush kicks in. What's wrong with running in the fresh air without having someone shouting like crazy about your greatness? Why do we need to feed ourselves with reinforcing statements of our own greatness? We are humans, we aren't great all the time, and we don't need to be.
And oh, almonds are tasty, but ice-cream is always better.