Envy. An emotion that occurs when a person lacks something that another has and wishes to possess it, to have it. Envy is one of the Seven Deadly Sins. According to Wikipedia, "envy is the pain or frustration caused by another person having something that one does not have oneself." - One word that is different from the other word jealous, which, according to Wiki again, is the fear of losing something to another person (a loved one in the prototypical form).
So are you an envious being? I am. Infact, I think I am easily envious of many things many people have. I might envy those who are richer or have their own cool gadgets like a laptop, hand-held games, bigger room, own bathroom, etc. etc. But rarely is my envy something materialistic. What and whom I envy are those who have natural talents or beauty or both brains and brawn put together. And I am also easily jealous.
If you think you do not envy anyone, or have never envied before, think again. It is only natural for humans to feel so; to become a green-eyed monster every once in a while. It is an emotion we possess. More still when we are in a competitive world. However, it is an emotion we should keep under control. To be envious, is to sin. When you envy, you tend to hate. And if there is no further control, that hate may turn into wrath (which is also in the list of the Seven Deadly Sins). That wrath may lead to something else.
So change this envy into kindness or admiration. If the other is better than you in something, don't dwell in self-pity or in Envy's chokehold. You might be better than the other at something else. Everyone has their own strengths. For all you know, someone else might be envying or admiring you for something you can do well. Let go of Envy and its desires and be confident in you.
"Let us not be conceited; let there be no rivalry or envy of one another."- Galatians 5:26