Envy is one of the oldest documented emotions. It's what led Adam and Eve to eat from the Tree of Knowledge. It caused Cain to kill Abel. It's the deadly sin that made Brad Pitt scream, "What's in the box?" As with most examples of envy in literature, those are all negative.
I envy Jillian Michaels' body, so I am working out for more hours every day and with a greater effort. I see people who run faster, so I train to become a better, faster runner. Envy spurs me to be a better person. I think it can do the same thing for everyone else, too