As a definite introvert, I am often puzzled by the extraversion impulse of most of my fellow humans.
Being among large groups of people is not energizing to me. It feels oppressive....
To me, this friend's perspective screams "insecurity!" He is afraid of being alone. He is afraid that if his chosen preferences aren't validated by throngs of others doing the same thing, being in the same place -- then the preferences aren't worth holding.
A few thoughts. First off, in my experience of psychology, we're bedeviled by impulses pushing us toward both dependence and isolation. Enmeshment, estrangement. This should be emphasized; Karl's right in seeing a lot of dependence in people. Here's the other thing, though: we don't tend to see the downside of estrangement. It's other people's problem. It's self-correcting, see? People who can't deal with other people don't deal with them for very long. They withdraw and withdraw and use proxies such as work or the computer to let them avoid the direct connection that they both crave and loathe.
Another little nitpick, and this is something I can't stand, and I call myself an extravert. People think they have to call themselves "extraverted." This is what I hate about popular psychology filtering through into lay terminology. Here's the big secret: introverts like people too! Introverts can be social! Introverts can be confident! And while most introverts like to think that we extraverts are the aggressive, bullying, loudmouth, centers of attention that we often are, here's another axe I have to grind: introverts can be real motherfuckers if you piss them off, but they will often work in ways so institutional that you can't directly confront them. But that's a little issue I have and which I'll probably address in the future.
Here's my take. I both love and despise crushes of people. In Istanbul my mother was experiencing claustrophobia as we pressed through a mass of people in a tunnel/bazaar passing under a highway. I didn't particularly like it but I delighted in moving through it, in cutting a course around families and clumps of Western tourists. My mother hated it and we didn't go back through a similar situation. Some of us need space; some of us carry that space in our heads. I am a nervous human being and I sometimes find my calm when I'm surrounded by chaos and throng and thousands of bodies. It's a strength and a weakness, depending on my surrounding, I suppose.
Another example. I hated working at a theme park. I was impatient with the flow of people with no discernible goal, their sense of urgent insistence only equaled by their tendency to clog walkways with the mass of their bodies. Their numbers didn't bother me, but their viscosity. When I am in parts of New York I feel like I'm in heaven. It's so dense with people and yet I do not feel them. Even in a crowded subway car people know their place. I have a feeling some of us would feel like they were in the Soviet Union when they saw that; I feel like it's something that you might see in anarchy. No coercion is needed to yield one's seat to the elderly, or scoot back to allow a stroller to pass. Though the Western world is deeply violent, and our industrial order is predicated on iniquity and death, one does not feel that it is essential to the courtesy that is possible among great numbers of people with goals and plans... I have seen great numbers of people interdependent and yet not nearly so desperate for each other as one might think.
I have not given up on dense civilization, and in truth, even those who long for comfortable seclusion and space had better hope for the survival of mass civilization as well. After all, if it does not work, where do you think all those urban millions will go? There is a far worse thing than concentrations of people, and that is a world covered in the semi-urban sprawl that, to me, offers neither the benefits of concentration or space.