The rules I truly care about are the ones that aren’t written down, like “don’t bother each other” and “keep your eyes on your phone screen at all times.” Sometimes, when I take a break from staring at mine and stretch my crooked little neck up to see how many stops I have left, I accidentally lock eyes with someone else. We frown at each other and go back to our screens. As it should be.

That said, every now and then, paying attention can be wonderful. I looked out the window of the B train one afternoon and watched as a woman who had been sitting opposite me took two steps onto the platform, looked at her hand, and then whipped her head back at the train with horror. Right then, the man beside me lunged at the man opposite me. I thought he was attacking him, but he was reaching between his legs because he’d spotted a diamond ring on the floor. He leapt toward the door and handed the ring to the frantic woman, whose face broke into a huge smile. It was as if she were getting proposed to all over again, except this time by a stranger speckled in cement. He apologized to the guy he’d jumped at and we all shared a laugh. It felt good. Thirty-five minutes later, I waved goodbye to the speckled man. He made a “Who the hell are you?” face. He’d forgotten we’d shared that moment and, honestly, that made it perfect.

I don’t want to romanticize the subway. It drives me crazy with delays and crowding. When I first moved to New York I was wowed with the possibilities for a dreamily inclusive future that the trains opened up. I would gaze starry-eyed at an elderly Orthodox Jewish man dozing beside a guy with a mohawk and a leather jacket reading beside a woman in a sari holding a baby, etc. Six years later I just want to get a seat so that I can trawl Instagram and eat my churros in peace.

Perhaps I wasn’t being naïve, though, according to the book “International Express: New Yorkers on the 7 Train,” about the busy Queens subway line where 80 languages are spoken. “A most remarkable characteristic of the process whereby one becomes an urbanite on mass transit is that the ethnic and racial categories that might seem to distance one from fellow passengers are usually and quickly dismissed as secondary,” the authors write. “This process of knowing-yet-ignoring whereby riders become ‘blasé’ New Yorkers on the subways is essential to the establishment of a community in transit.”

Still, I worry that we’re not all in it together. I wonder how many rich people ever use the train. I wonder why Gov. Andrew Cuomo and the M.T.A. are prioritizing the wrong solutions, and I wonder if I can stand many more years of unreliable service. Then something happens that gets me all mushy again.