You know, if your older brother decides to play with the cool kid on the block instead of you, as the younger brother, you might feel really left out and you might think that nobody likes you or nobody cares about you. And if a couple more situations like this start to happen, it can really start to develop a belief that you are not worth hanging out with. You know, no one really likes you. You're not worthy of love. And you'll carry that with you subconsciously through life, having no idea that that belief is there or why it's there, but it will serve as sort of a fundamental character traitwoven into your story.