Boston roadies do not like me

So I've been actually getting out on the "road" bike quite a bit this last week (road is in quote because it's actually my cross bike with road tires on it) and I've noticed a kind of sad trend -- roadies don't acknowledge each other. Or, at least, roadies don't acknowledge me.

So, a little back story -- where I come from, the uninhabited woods of Maine, most of one's ride consists of being totally alone on a road wondering when the next pickup truck is going to try to run you off the road. Seeing other bikers is incredibly rare, so of course you acknowledge their presence. "Greetings fellow cyclist, it is heartening to see that you too have survived the swerving pickups and nonexistent shoulders long enough to pass by me in the opposite direction! Good day to you!"

Really though, you always give the other guy a nod or a wave. He's a comrade.

But now, as I dawdle around Boston, the nod is coldly ignored by every serious cyclist I pass. It would be one thing if we were riding in dense traffic -- a dude's gotta look out for cars, you know. But this happens with 100% frequency out on the "country" roads around 95, too.

So what's up with this? I know very little about roadie culture, so am I just an idiot? Do you, actual road racers who read this blog (yeah, both of you), acknowledge one another if you pass out on a ride? Or are you so intent on your Powertap that you can't be bothered?