I've done a lot of city riding over my lifetime. My formative years and racing years, Boston. If you want to live long riding in Boston, you don't spend a lot of time looking at your cassette. On many streets, those looks simply don't happen. Solid lines of parked cars and potential doors with traffic on your left beside you. I got caught many times when lights changed not knowing what gear I was in. Now I was not on a recumbent so that stopped look back was easy and lifting the rear wheel to change gears not much harder.
I often found riding the fix gear and knowing exactly what my start-up was going to be kinda nice, even if some of those starts (esp uphill) were hard.