I think it’s a matter of selfish self preservation. Most people don’t want to enmesh themselves in someone’s difficulties or problems. It’s a drag and brings people down. So they protect themselves. And if someone has great news, it can make another person feel they’re not in the best place in their own lives, they make comparisons so it’s hard to hear. Again self preservation. Many people cannot step outside themselves to truly help another or be happy for someone when things are going great. This is especially true of people who are depressed or unhappy, and many people suffer depression and dissatisfaction in their lives.