I moved to Philly and got a road bike from a friend because its easier than skateboarding or walking everywhere. I stripped the gears off and made a SS because, well, theres no hills in Philly and its just extra weight. Then I got hit and my back rim got taco shaped, so I went to get a new one. One of the guys at a LBS said he had a spare flip flop layin around he would sell me, so I took it. When putting it on, I decided I would like to try the fixed cog rather than buying a freewheel and installing it, then I fell in love. Now I live in DC and still love my fixie, although I wouldn't mind a geared bike for some of the rides that people go on around here. Who cares why people ride bikes, what kind of bike it is, or how they got into riding fixed. Everybody has their story and their taste. In my opinion, you can't ride fixed without liking it. Every time one of my friends gets on my bike I see a huge smile on their face.

Riding bikes makes people happy.

I ride a fixed gear because it goes with my haircut.

I ride fixed 90% and my backup road bike the rest of the time and the thing I've noticed about the fixie is that I almost always have to ride it as fast as I can. It starts with hills. The easiest way to climb on a track bike IMHO is to go as fast as you can because otherwise you're more likely to end up lugging it at the top. But even on the flats I feel driven to push it to the limit and the same goes in traffic.

Funny thing is that it's so easy to ride slow on a fixed gear because of the way you can control your speed with the pedals. I do enjoy riding slow with friends, especially at a Critical Mass where you don't have to worry so much about the traffic.

I commute about 100-170 miles a week depending on how many days I caa ride.