I've heard this line countless times on the internet and otherwise, but I never really wondered what it meant or why it is until recently. I've found that being alone for a while can be nice; but when I'm alone for too long, like a few days, I start to feel restless and stir crazy. I'll crave the social interaction. Its not really a problem or anything, but it makes me think. I feel like it should be something I can control, but it feels as innate, subconscious, and uncontrollable as one's sex drive.

Could anyone tell me why this is? Are the reasons cultural/psychological or is there really a social physiological element behind humans as a species? Is communal interaction a necessary component of human experience, or just an added luxury of it? Comments, theories, links? Post em here.