A few weeks ago, as I was getting out of a taxi, a bike messenger whipped by me, and I was thrown to the ground. I hit the concrete pretty hard, but I landed on my posterior. As a century of cartoons has taught us, that is a funny way to fall and one that causes no real pain. That’s untrue, as I discovered. It hurt like hell, with shooting pains down my right leg. I had to hobble along for several blocks, finally limping into the subway, where I was lucky to find a seat.

Or maybe it wasn’t luck. It was raining hard that day, so when I fell, it was directly into one of those curbside puddles, leaving one pant leg entirely soaked and streaked with grime. And I’m only calling it “grime” because I don’t want to know exactly what it was. It turns out that when a disheveled gentleman in half-wet pants limps onto a subway car, muttering furiously about “those damn bike people,” other riders will move instinctively away. New Yorkers don’t look for trouble.