Jealousy, Envy
Feelings have a way of wearing us down. Fix your attention on what someone else has and you lack, and the result is usually a sour mood. Being glad for another person can feel strangely difficult when they've landed the very thing you've been wanting. But joy doesn't have to come at a cost to you. If you and I are chasing the same sort of goal, I can still take real pleasure in your reaching it first, and from that angle their good news stops feeling like my loss.
I learned this with a pregnancy. Years ago, while I was trying to conceive, a cousin of mine, quite a bit younger, got there ahead of me. Two roads opened up in front of me. One was to sulk, to sit with my empty arms and let envy do its work, which is to say make me miserable. The other was to step into her excitement, to share in the waiting for a new life. I chose the second. As it happened, I was already a little bit pregnant the day my mother passed along the news about my cousin. I just had no idea yet.
The work isn't finished. I still catch myself resenting what other people manage to pull off, and I still have to do the switch, trading the sad reaction for a glad one. It rarely comes easily, yet it reorders how the whole day looks. There's a parallel to holding onto anger at someone long after they've left your life and can't touch you anymore: the grudge accomplishes nothing except keeping you stuck. In the end we're kin, at minimum in God's accounting, and when one of us comes out ahead the sane response is to celebrate it. That gesture does more for the one who makes it than for the person being cheered.