Naturally, we tend to talk about whatever we happen to be paying attention to or thinking about. So excessive talking about oneself is a symptom of excessive thinking about oneself. Why would someone do that? I think that it’s a logical consequence of having “getting people to like you” as your highest value. If that’s the case it’s only natural to model other people’s view of you in your own mind and try to make it as pleasing as possible. I think that if you made a few important decisions that indicate to yourself that you have some other guiding purpose in your life (it could be as simple as openly disagreeing with someone about an issue you care about, or devoting your attention to a project that interests you in and of itself). Paradoxically, I think that MORE selfishness might be the answer (just like how attending to your heart rate can sometimes serve to slow it down).
So others do that too?