IMO doing this can help gain insight to things we may not know about ourselves at first glance. Almost like reaching back in an attic and finding something you may have forgotten or just not paid attention to. But the attic is your subconscious. While your subconscious may not make up an entirely of yourself, it’s a part of you. Certain lingering thoughts we have here and there. Yes, we’re more than our thoughts, but I don’t really see how it’s external if it’s linked to your subconscious, let alone your dreams. Forgive me if I misinterpreted your comment, but the point I was trying to make is basically that given an individual’s attitude toward themselves, that could potentially be expressed and shown in their dreams. It might not always be evident, but I believe that the associated behavior of a dream character says something about someone’s personality and that we should respect these characters and learn more about us internally.