I  envy birds because they can fly to the place that they want to, but we have to apply for visa. (<o-o>)

I don't get envy of other people ,no matter he or she lives well, rich or luxurious. Only live with my own dream ,each step of progress makes me feel better than before. Everyone or everything is not perfect,  that means there must be weakness on their whole body or processing ,even result would bring us sadness or disappointment. I would accept it if I have a trial or really love.

When you say "It prevents them to live a normal life", could you be more explicit on what is a normal life? I'm not sure there's a universal, absolute definition of a normal life, so... I'm understanding this as causing disturbance in their relationships (But then again, maybe 'having good relationships' is not an absolute requirement for a normal life). 

Envy shows us our deepest insecurities and fears, but also, as you, said, it's human.

I envy people who advance well in their career, because I feel I may never make it in life, find the means to subsist; I envy people who appear to work in a job they love, because I'm afraid I won't find one myself and will be miserable. I used to envy thin people because I feared I wasn't physically attractive. 

On top of that, I used to envy people who were popular and had many friends, fearing I couldn't be poplar myself because I had poor social skills. I figured out later that it's easy to befriend a lot of people and have everyone liking you, superficially; but then I figured there's no need for me to be envious because I don't actually need that. I figured that maybe I'm envious of things that don't truly matter to me. Envy may be provoked by what I think I may need,(and don't have, but others do); envy's seed may be in fact planted by societal values & ideals... To avoid envy, develop critical thinking and be clear on what you need...