We all want to be the kind of people who are happy for others when they experience success or a cause for celebration in their lives, but it isn't always easy. Sometimes powerful, dark feelings come up at times when decorum dictates that we should be feeling the opposite. Instead of reaching out and celebrating for our loved one, we may feel the rising up of our own pain. This pain may arise because we feel jealous of our friend for having something we don't have. It may arise because our friend's success will lead to us losing them in some way. And it may arise for reasons we don't yet understand. The important thing is not to brush it under the rug, but to take it seriously and look at it; suppressing it will only make it worse. At the same time, we need to be sure to find a way to congratulate our friends and celebrate their successes as if they were our own.
Extending ourselves to celebrate the happiness of others requires a generosity of spirit that we sometimes find only in the process of doing it. So when your best friend moves to Spain with the person you had a crush on, tend to your broken heart but throw them a going away party too.
Sympathetic joy is a great antidote for resentment or envy. And we can practice it for people we just hear about - we don't necessarily have to know them personally. I recommend being intentional about this practice. Actually try to think of people for whom you can have sympathetic joy. Don't just wait for it to occur to you!