It depends on the individual. What their likes, dislikes, needs, and mindset are. For some joining an organization can be very beneficial. More money, better position, more power, etc, but may have to be willing to work hard and in some cases, become ruthless to get there (Mindset). For others joining the same organization may not be as beneficial. because they aren't willing to work as hard or become ruthless (Mindset). Some may join an organization simply because they feel the need to be part of something. Which can be beneficial or make things worse. Those are just a couple of small examples.
Am I a joiner? No, not really. I never felt the need to join anything to get along in life. I have always been content with what I've had and what I have now. No need to join anything to enjoy that. :)