To feel envy is to feel diminished in one's sense of self-worth by the positive attributes or success or well-being of another. It is in a certain sense the opposite of Schadenfreude. The envier is pained by another's success or well-being, sometimes to the extent of wanting to destroy what the other has. The 'schadenfreudian,' to coin a word, is pleasured by another's failure or ill-being.
Envy is classified as one of the Seven Deadly Sins, and rightly so. Much of the mindless rage against Jews and Israel is the product of envy. Superiority almost always excites envy in those who, for whatever reason, and in whichever respect, are inferior.
This is why it is inadvisable to flaunt one's superiority and a good idea to keep it hidden in most situations. Don't wear a Rolex in public, wear a Timex. It is better to appear to be an average schmuck than a man of means. In some circumstances it is better to hide one's light under a bushel.
If greed is the vice of the capitalist, envy is the vice of the socialist. This is not to say that greed is a necessary product of capitalism or that envy is a necessary product of socialism. There was greed long before there was capitalism and envy long before there was socialism.
One cure for envy is moderate, the other radical. I recommend the moderate cure.
Consider the entire life of the person you envy, not just the possession or attribute or success that excites your envy. You say you want what he or she has? Well, do you want everything that comes with it and led up to it, the hard work, the trials and tribulations, the doubts and despairs and disappointments and disasters? Unless you are morally corrupt, your envious feelings won't be able to survive a wide-angled view.
The radical cure is to avoid all comparisons. Comparison is a necessary condition of envy. You can't envy me unless you compare yourself to me, noting what I have and am as compared to what you have and are. So if you never compare yourself to anyone, you will never feel envy for anyone.
The radical cure ignores the fact that not all comparisons are odious, that some are salutary. If I am your inferior in this respect or that, and I compare myself to you, I may come to appreciate where I fall short and what I could be if I were to emulate you.
That being said, "Comparisons are odious" remains a useful piece of folk wisdom. You can avoid a lot of unhappiness by appreciating what you have and not comparing yourself to others.
As for the bombshells at the top of the page, the blond is Jayne Mansfield and the other Sophia Loren. The picture illustrates the fact that, typically, envy involves two persons, one envying the other in respect of some attribute. Jealousy, however involves three persons. This why you shouldn't confuse envy with jealousy. This is jealousy, not envy: