Jealousy is a feeling of resentment against a rival or a person enjoying success or advantage. Jealousy makes you feel unhappy and angry towards someone especially when they have something that you do not have. Sometimes you are also jealous because someone who knows quite well that you exist, prefers the other person over you.

jealous

A lot of times people are jealous and do not know it while other times they are very much aware of their feelings of resentment.
Feelings of jealousy can be poisonous, toxic and has led those who felt it to do stupid things which often leaves them in a state of regret.

It is a very dangerous feeling and can destroy friendships as well as marriage.
In order not to entertain this horrible feeling, be happy with yourself and be happy for others. Appreciate where you are at the moment and be positive for a better tomorrow. 

Princeton Hines