It showed me the amazing range of speed you can get out of just one fixed gear, and just how fast you can go in gears I used to laugh at, like 42x16. You can hit 30 pretty easily in that gear if you really spin it out.

I had gotten lazy with my geared bikes, I would keep the same cadence all the time, and then use my gears to always have my legs turning at the same speed, at all times. That's very bad, I learned, after riding fixed. I vary my cadence a lot more these days on my geared bikes, and spin much faster than I used to when I want to go fast, instead of just dropping into a big gear, and THEN trying to apply power. Bad bad bad.

Riding fixed will definitely clean up your form, but it's easy to crash if you forget you can't coast after hitting an obstacle like a pothole unexpectedly. Your hard-wired knee jerk reactions you'd use on a geared bike won't work, and can cause a serious crash if you don't stay alert.