Envy is unavoidable in the world of game development - too many insanely talented folk out there creating amazing experiences. Only natural to compare and critique your own work more. I think envy is healthy for the most part, though; inspires us to greater heights yadda yadda etc.
Personally, I try to convert that envy to a learning experience. If somebody has created something successful - it's good to work out what contributed to that success and apply it to your own work (I'm talking more about strategy/production/business here, less art/design which is obviously not so cool to copy...).