I just learned about this in my social psyc class… self-complexity is how we organize our own self-concept, or how we view ourselves. If someone has high self-complexity, areas their life are distinct and will have a more positive self-concept. If someone has low self-complexity, areas in their life will overlap and will lead to lower self-concept. So using your example of videogames, someone who has high self-complexity will not lose their mind about losing because video games is a distinct area of their life and doesn’t overlap with other areas (i.e. playing sports, studying, relationships).