I rode the part-time job up to UBC for a little winter trail riding today. Actually, most of the ride was pedalling there and back again. The ride through the endowment lands was pretty amazing, with virtually nobody walking or riding the trails, and almost no snow to speak of, and very little mud. I had a really fast run down to the beach that reminded me of why I need to put gears on that bike again; I could have gone faster were I pushing a bigger gear. And then, having only one gear is beneficial too.
There is something neat about riding single-speed. You can only do so much, so you only want to do so much. (Also, you definitely have to work with what you've got, get on top of your gear on hills, and learn to spin like a mad man if you want any speed.) I think that is part of it. Does that make sense? What I mean is that having only one speed simplifies things, which in itself might seem obvious, but it does so in a surprisingly significant way