ya know I never see other cyclists on my commute either and I do dig the solitary aspect of the ride, but yesterday on the way home I finally found another biker waiting at the first traffic light on my commute. We chatted briefly and I drafted him for a mile or so, then told him i'd take over in the front for a few which he was happy to hear....we rode like that for another mile or so and then switched back. As he passed me he noticed I was riding single speed and says "Let me put these gears to use a little, I'll move up"

we cruised for another 2 or so miles until he split off to circle back home, exchanged a hearty thumbs up and said peace. Totally awesome and friendly ride home and a cool experience.
...but next time please make it a cute girl.