You have to find your own internal motivation. Ultimately, it does not matter who you are. Even if you think of yourself as a good person, it is not worth anyth

You have to find your own internal motivation. Ultimately, it does not matter who you are. Even if you think of yourself as a good person, it is not worth anything unless you let your actions define you. It is up to you to decide if you want to be that selfish person, with all the benefits you mention that come with that. Or you can decide to do what you know is right and really be the person you want to be. Think "do I really want to be the person that..." before you act.