Who am I jealous of? Is my jealousy made more intense when my sense of self worth is in question? The Torah teaches us that Rachel wondered why Leah was blessed with many children quickly and easily while she seemed unable to have her first. She began to feel badly about herself. It must be Leah is a tzadekes and I am not worthy. Maybe Hashem is punishing me. When we go to these darker thoughts, it is counterproductive and doesn't help us move forward.