Howard Beach/JFK, A

There was the first ride, 20 years ago by now, from JFK to Washington Heights with my parents. My cousins had given us instructions: Just take the A. So we took the A for an hour and a half, from Queens, through Lower Manhattan, snaking up the west side past the park, through Harlem, all the way to 181st street. It was July and hot. I was ten years old with an unfortunate short haircut in the middle stages of growing out, wearing a halter top with daisies sewn on it. The subway ran on tokens then—we fed bills into the machines and filled our pockets with them. I dropped one by accident and put my face flush against the floor to find it, the way my dad had taught me to spot a lost object. My mother shouted, horrified. She didn't understand why we couldn't just take a cab.

23rd St., F

The train pulled into the station and I looked up from my book and saw, through the dirty, smeared glass, the first boy who really broke my heart. The one who had sprawled across my bed like it was his, happy to lie in a tangle of sheets for hours. Who'd taken me to the beach for the Fourth of July and held my hand as we ran away when the fireworks exploded on the sand, who'd written me notes that felt suspiciously like love letters on paper torn from legal pads, and who always remembered my birthday. But it had been six years and I had married someone else. When our eyes met, I remembered that I wasn't wearing any makeup and that my hair was dirty, but my hand rose in a wave. My face caught in a smile, and he was smiling too. And we stared at each other for a frozen moment before the train heaved and sighed and pulled away.

34th St., Penn Station: 1/2/3

I fell asleep on the train and woke up in a panic and got off and then realized I'd gotten off too early, so I sat down on the deserted platform to wait for another train to come. It was two or three o'clock in the morning and I was 17 and still new to the city, wearing my go-to stretchy black pants with the dip in the front that I thought made me look great but really made me look like I'd wandered outside in my pajamas. I waited and waited, and a man started walking toward me on the platform, the only other person around. As he got closer, I saw that all of his features were pushed to one side of his face, like one of those fish where both the eyes are on one side and the other side is flat. He walked past me, both of his eyes meeting mine without turning his head, and continued down the platform. Eventually, the train came. I would never be sure if he was a burn victim or born that way or if I'd imagined the whole thing.

14th St., Union Square: 4/5

It was the end of one of those perfect summer afternoons, and Adam and I were running to catch the express train back to Brooklyn at Union Square; we could hear it pulling into the station from the top of the stairs. We were sweating as we bolted down the staircase, trying to dodge the obstacle course of kids, moms and strollers clogging the platform, and as we got to the bottom, we both heard the noise—the retching. One of the kids was projectile vomiting. The whole thing happened in slow motion: a stream of puke arcing into the air, and Adam leaping over it like something out of The Matrix. And then we were in the train, all clear, a transit miracle, the doors closing safely behind us. We laughed all the way to Borough Hall.

West 4th, A

The train was packed, commuters squeezing past bunched-up tourists to find more room in the middle of the car. A girl in her early twenties got on with her parents, guiding them through the crowd, and we all held on to the same pole, they still clutching playbills from a just-attended Broadway show. The whole family was smiling, the daughter laughing and explaining things to her parents, the parents hanging on her every word. The dad had the same ambiguously olive skin as my father, and was wearing the kind of hat I would have been embarrassed by if my dad had chosen it. But I was 28 and would never get the chance to be embarrassed by my father again: He'd died two years before. My eyes filled with tears watching the three of them, their faces spread in matching grins, but I stared at the floor until I watched their feet exit the train at Fulton. After that, I closed my eyes and cried, silently, until I had to transfer at Jay.

14th St., Union Square, N/R

It was my first winter in New York and I was wearing my first real winter jacket, a brown tweedy peacoat my mom had bought me from J. Crew. There was snow on the ground and swirling in the air and I was about to walk up the stairs and out of the station when I noticed the man in front of me was wearing a hat, a puffy ski parka and snow boots, but no pants. His bare ass jiggled as he climbed up the stairs in front of me, unhurried as he stepped out into the snow.

Second Avenue, F

I was 20 and living in my first apartment out of the dorms, on First Avenue and First Street—we called it The Nexus. I had wanted desperately to be a waitress for the summer but I didn't have any experience, so I got a job as a hostess at a mostly-empty restaurant in the bottom of a hotel on 46th Street. To be there on time I had to leave at 6:20 a.m.; there was hardly anyone else on the subway that early, but you could tell we were all going to the same, menial jobs. One morning I saw a homeless man taking a shit on one of the blue seats in the station, the ones that are carved into the wall. Later that fall, the seats, which had been peeling and flaking, were repainted a fresh, bright blue: They looked as good as new.

23rd St., A

My roommate Lauren made friends with a group of guys a few years older than us who were rich and liked to spend a lot of money at clubs, so we went with them. It was 2004 and we were 19 and the big night to go out was Tuesdays; there was a strip of new places on the west side where the bouncer unclicked the velvet rope and waved us in and a girl would stamp our hands and someone else would show us upstairs to a table. I always had to wake up early to go to class, but we stayed out til 3 and 4 a.m. and drank bottle service and danced with each other and flirted with strangers, and when it was time to go home, Lauren and I would walk to the subway station in Chelsea and wait for a train to take us back to our dorm in Chinatown. While we waited, we imagined our parents in California being terrified if they could see us now, and wondered if we should have just asked the police who were parked at the gas station on the corner if they could give us a ride home. It never occurred to us to take a cab; we were trying to be responsible about spending money. One night we waited for an hour, and when the train finally pulled in it was the money train, the one that used to go from station to station transporting sacks of cash. As it pulled away we saw a group of MTA employees in one of the cars, playing poker at a card table. Afterwards, whenever I told people about the money train, they thought I was hallucinating, but then I saw an old one in the subway museum and it turns out the city retired it in 2006.

8th St., N

A boy I'd always been a little bit in love with came to New York in January of our freshman year of college, but he wasn't really there to visit me. He brought his new best friend and they looked like twins, with shaggy hair and rumpled sweaters. They went to school in Minnesota. When they arrived, I took them sightseeing. We got on the train closest to my dorm room and I said, overdramatically and with a hand flourish, so this is the New York City Subway, like I was an expert welcoming them to my town. I had lived there for five months. They shrugged and looked at the floor and sort of at each other and then one of them said finally that they'd already ridden it, they'd actually been here since yesterday. Originally I'd thought we might end up together after he came to visit, but the trip came and went and we didn't even really wind up staying friends.

Whitehall St., R

I was wearing flip-flops for my commute to work and leaning against the subway doors, reading the New Yorker, already tired of the hot weather. Suddenly I felt something warm and wet on my foot. I looked over and saw a child giggling and leaning against the pole, and I assumed he'd spilled his juice box and was annoyed that my foot was going to be sticky. Then I looked closer and there was no juice box. He had peed on my foot. His parents were too busy playing on their iPhones to notice. I got out and went to work and told everyone what had happened, and the whole newsroom laughed. Someone asked what I did with my shoes and I said I'd thrown them out, but it was my only pair of flip flops so I actually just washed them off and kept them.

Delancey, F

It was a few days after I turned 23, and we were going to Mexico. But the night before we were supposed to leave, I realized I'd lost my passport—I'd dropped it at my birthday party, and it had traveled back to California with a friend of a friend who had been too drunk to realize he'd put it in his pocket. Adam, who was 29 and ready to be a grownup, could not believe it. Trying to prove to him that I could be a grownup too and salvage our tickets, I took the train to the airport in the middle of the night and begged the gate agents to let me get on the plane without my passport. They wouldn't. But they did take some mercy on me and charged me a $300 change fee and $200 to ship my passport to New York on the next flight from California, and they rebooked the trip so we could leave the next morning. From the airport, I texted Adam, by way of apology, I love you more than anything, I would marry you tomorrow. He didn't respond. On the F train back to our apartment, exhausted from being awake all night, I ran into a girl I knew from college who we called Crazy Russian Ellen. She was on her way to work. She taught naked yoga and didn't shave her armpits and liked to go to Burning Man and had recently landed in the hospital after overdosing on mushrooms. She gave me a hug and wished me good luck. It was the first time I could remember being less put together than she was. In the end, Adam and I made it to Mexico, where he forgot to be mad at me. Four years later, on the side of a hill on a windy day, he married me after all.

Meena Hart Duerson is a writer, reporter and senior editor @TODAYshow's

[Image by Tara Jacoby]