From among all… adverse conditions, the foremost is jealousy. Jealousy can rob us of our freedom and interrupt loving relationships between people. Jealousy occurs when we cannot tolerate others encountering situations that seem to involve more happiness than what we have. When we continually feel the need to have others beneath us and none equal to us, that is jealousy. When we are controlled by jealousy, we only feel comfortable when others come to us for assistance; we only feel at ease when others are looking to us with hope. We cannot stand being in situations where others have something that we need.
When we become jealous, we are not willing to see the positive qualities of others. Whether we are alone or in a group, when we are overcome by jealousy our eyes are not willing to see the good things in others; they are constantly looking for other’s faults. We build up intolerance toward the faults of others. In particular, when we see others enjoying good fortune that exceeds our own, we cannot stand it. In this way, we create extra and superfluous difficulties for our minds to deal with.
A better approach would be to pay more attention to our own conduct than to the conduct of others. ~17th Karmapa