Jealousy is a negative emotion, and personally, I try to avoid it, as it leads to negative consequences. I think some forms of jealousy are indicative of low self-esteem, or perhaps an nonrealisitc view of one’s success or attributes. My best response to jealousy is: “Don’t compare yourself to other people, they are probably more fucked up than you realize.”
Jealously is human nature, it is something you need alot of will power to control. I do not think it is a bad thing if you keep it to yourself but if you start to do anything violent because of jealously it is a serious problem and is definately not right.
It depends on what you make of it. If jealousy motivates you to work hard to get the same things (or better things) than others then don’t stop being jealous: exploit it to your advantage. Focus on it whenever you feel discouraged.