The midda of קנאה , jealousy, can ruin a person's entire life. It can cause him to always feel lacking and dissatisfied. The Orhchot Tzadikim writes that it could lead a person into doing the worst averot . It is a Midda that everyone is born with, and it is up to us to uproot. One of the things that people are jealous of is other people's material success. There is so much more to life than money and materialism, and it's not worth wasting time and energy agonizing over. I recently heard of a man who spent years planning and then having a yacht built for him which cost over $90,000,000. Lo Aleinu, he got sick and was never able to go on it even once. On his deathbed he repeated over and over, "What is it all worth? What is it all worth?" The only thing that is everlasting in this world is Torah and Mitzvot. The Orhchot Tzadikim writes further that when a person is jealous of other people's looks or wealth or any other strength that they may possess, he is in violation of one of the most basic principles of Emunah, namely, that Hashem runs the world and gives each person exactly what he needs to do his job. When someone complains that he doesn't have what someone else has, he is saying that Hashem is not being just. He is complaining against the One who decided who got what. If someone could give himself the proper chizuk he can turn that potential flaw into a great avodat Hashem. The next time a person sees what someone else has and feels bad that he doesn't have it he should stop himself and say, "Hashem decided who gets what. Hashem decided that I shouldn't have this right now. I am going to believe in His hashgacha and stop desiring it. I am going to trust that Hashem gave me what I need to do my job and I am going to be happy with it." This would be such a great avoda. The Orhchot Tzadikim writes further that jealousy could also lead a person to go off the derech. Sometimes what a person desires is something that a wicked person possesses. So he says to himself it doesn't make sense that the wicked get all the good things while he, who he feels is righteous, doesn't. He causes himself to ask the age old question of why the wicked prosper. It is only because of his jealousy that he decided what the wicked man has is good and that's what causes him to ask this question. He may then say it doesn't pay to be righteous. I might as well also do evil, maybe I'll get that blessing too. Material success does not necessarily mean it's a blessing. There's a concept of materialism being just the opposite. Nobody knows who is truly enjoying blessing and who isn't. Hashem is righteous in all of His ways. He rewards good and punishes evil. The Orhchot Tzadikim adds that jealousy makes a person hate others for no good reason. He is bitter at the people who have what he doesn't have, and he could only be happy when they lose it. One of the greatest antidotes to jealousy is strengthening emunah. The more a person believes that Hashem is the One who decides who gets what and that each person gets based on his purpose in this world, it will be easier to focus on what he has rather than desire what everybody else has. Every time we overcome jealousy and believe in Hashem's hashgacha we turn a potential aveira into a great mitzva.