Good question, but this is a tough one to answer in this format because there are quite a number of things that could be going on that give the appearance of “deaf ears.” The best short answer I have is to look into Marshall Rosenberg’s Non-Violent Communication (and he has a great book by that name). But here are a few of the things that could be happening. First, people don’t generally like unsolicited advice, especially about their flaws! So part of it has to do with how you “point things out,” and whether the other person has any interest in working on those things from their own motivation. Second is the problem of developmental change which it seems you got some understanding about. But pointing things out to others is usually a tricky business, and it’s important to understand your own motives as well in doing so.