I think that might be a pit pessimistic of you. I have friends in real life that I only take about school with, ones that I only talk about media with, ones that I only talk about the latest geekery with. It just means you're casual friends and not best friends, and there's nothing wrong with that.

Also, are you telling me you've never said something like "Would have written fic, but slipped on some ice and broke my wrist" or similar? Because if you have, that's real life, and if you haven't, I admire the hell out of your separation techniques.