I don't share good news immediately. I just test my control level over myself with it. I can easily keep things inside me for a long time, but still I choose to share after 9-10 days, as at that time I feel assured that I have full control over my emotions. Not something to do must, but I need to check it from time to time if I am losing control over myself.
But there are a few people who at least share their good news with me. Maybe my contribution to their life is good enough for it.