If you aren't good at loving yourself, you will have a difficult time loving anyone, since you'll resent the time and energy you give another person that you aren't even giving to yourself. ↗
I think the character does tend to suit an episodic thing, because what's fun about him is that he doesn't care about anyone else, and it's very difficult for a main character - a lead character - in a movie to not care about anybody else. ↗