How nicely this thread has evolved in my absence. Great thoughts, everyone. Other than our adorable extrovert, it seems most of you had to first work through your anti-world programming and then slowly build new friendships. Bravo to you all. I have a few specific comments.
Finally-free – It sounds like you might be an introvert, like me. I fool many because I do spend so much time with people and socializing. But at the end of the day, I need my alone time. I regenerate alone. I relax alone. But this is not loneliness if I choose to.
Void - I respectfully suggest that any animal that socializes for general protection (keep from getting eaten) is distressed when separated from the group. This would include all herd animals and simians. I think loneliness is hard-wired in to our makeup, rather than an abstraction. This is the primal urge that sends the bleating lamb back to it's mother.
Scully – “I've experienced loneliness in a stadium full of people.” Oh, yes, I’ve felt that wrenching pain. Especially when walking in for the first time and wondering if there is anyone I could connect with.
When sensing the isolation of belief as you describe in your closet (does anyone understand me?) I react in anger. I write. I roar silently.
Cognizant Dissident – I would agree that loneliness is a state of mind as far as it is a choice. The author I quoted holds special meaning for me because he founded a society to integrate the mentally handicapped. The rejection that this group feels is intense and real. His homes, L’Arche, invite able minded people to live and eat in the homes with these most special people in our society.
Slimboyfat – I haven’t seen Schmidt. A modern take might be Up in the Air, much less bleak (I am betting) and starring George Clooney. A girl's gotta love that.