Envy truly is a terrifying concept. I think envy is the first step to our journey towards betterment, when we see others getting happier/more successful, we get jealous, and that we recognize the things that we have been lacking. Envy helps us to be more motivated to outdo everybody else, but there's also a stopping point to where we must be happy with what we have.
You are right.Envy is a good quality.