This is the thing that really annoys me, the suggestion that I have an obligation to solve the personal-interaction needs of my co-workers.

I have become genuine non-work friends with some (former and current) co-workers. But there are many with whom I have no interest in being friends, or even talking to them for one second more than is necessary for us to get our jobs done, and that's ok. I shouldn't be forced to fulfill their social needs; that's their job to do on their own time.