Most people I know do "single subject" socializing--whether it's with extended family, co-workers, social or political causes, common interests(like sports, theatre, music or automobile restoration)--and the conversations and related interactions tend to exclude those that don't have a long time connection to the subject.

If you fall out of the loop for some reason(like changing jobs or getting divorced, or selling your Camero), or simply have had enough and run screaming from the room, there isn't much of anywhere to go where people aren't either total strangers or deeply involved in something that you aren't.

And so it goes...