Early last spring, I became a commuter. I was not born a commuter, nor did I become one by accident. When I signed up for a course at Columbia during my junior year at Princeton, I told myself that I had also signed up for a new identity. I was now one of the people who spend time in trains, in train stations, in subways, walking furiously to make it to my destination on time. In my imagination (fed with TV ads for cell phones and chewing gum), the commuter was hardcore. The commuter did not stop to talk to people. In the subway, the commuter stared straight ahead or glared at a magazine. All transit time was spent checking voicemails and emails on BlackBerries.
Embracing the role was not unduly difficult. Each Tuesday, I would change into my commuter clothes — black pants, boots and a big leather bag to hide my youth in. On entering Penn Station, the first step was to check my hair in my reflection on the train window. Reminding myself that commuters don't get lost, I would walk purposefully toward the wrong subway line. Standing at the tracks, I'd realize that signs are meant to be read and sometimes followed.
The third week into my experiment, I decided I was good at it. I was drinking lots of coffee, wearing higher-heeled shoes, talking fast on my phone on the way to the No. 1 to 116th Street and ignoring perfectly the man who burst into song when he finished selling contraband DVDs.
The way back to Princeton was always less exciting. By eight p.m., an exhausted Penn Station was attempting to sleep. The jostling crowds had gone home. But I was determined to remain a commuter, albeit one who secretly grabs a double-cheeseburger at McDonald's for dinner.
One Tuesday in this haze of acquired personalities, I decided to supplement the dinner transaction with pretzels for a friend. With my own Combo No. 2 wrapped in a brown bag, I did the commuter walk to the Auntie Anne's counter even though my train didn't leave for another 20 minutes.
"Hi, could I get an original and a cinnamon sugar?" The commuter, in my mind, doesn't have time to say please.
The commuter looked at her silver watch rather than the person behind the counter.
"That'll be $4.95, please." Not "that'llbefourninetyfive." Even though I was brusque, she was patient.
I reached in my bag for my wallet only to find that I was 95 cents short. I pulled out my credit card.
"We don't take cards, just cash."
"Oh my, really ..." the commuter drawled. Inside, I knew that this was old information.
"Well then," the commuter continued, determined to keep face, "why don't you just replace the original with a small Diet Coke?"

"Are you sure?" The question was arresting. For the first time, the commuter paid attention to the person behind the counter. She was young, almost my age.
"Yes. I'm pretty thirsty anyway."
"That'll be $4.20." Not "that'llbefourtwenty."
"Well, I just have four ..." The commuter's voice can falter sometimes.
"That's perfectly fine." And sometimes the commuter's face is saved by people behind the counter.
"Thank you so much. I'm terribly sorry about not having all the change." I was embarrassed, apologetic. I walked away, now clutching two bags, the commuter walk a little clumsy.
In the train, hunger overwhelmed me, and, after wiping mayonnaise from the double-cheeseburger off my chin, I opened the second bag for a small sample. Two pretzels, one cinnamon sugar and one original, stared back at me.
The commuter fled.
My world shrunk to a couple of mayo-soaked napkins, flat Diet Coke and two pretzels from Auntie Anne's. I tried to recall the girl's face, but only the baseball cap and a dark ponytail came back. I looked down to see crumbs on my coat lapels and mud stains on my boots. I wondered if I had been in her place and she in mine — would I have hated her thousand-dollar guts? Around me, people were boarding the train as if nothing extraordinary had happened. They were all in the world of the commuter, and I had landed hard on a not altogether unfamiliar planet.
In books, it's called "the kindness of strangers." In movies, it comes right at the end because it helps with the happy endings. In the world of the commuter, it is a myth. When experienced firsthand, immediate reactions are those of utter disbelief. Later reactions range anywhere from trying to forget, to deconstruction of the event until it is no longer human. Finally, The New York Times will run an article about how kindness is governed by certain hormones which are dictated by a tiny gland that nobody knew about. A scientist at Stanford will find a formula that predicts the time people are at their nicest. The commuters will read about them, swallow them whole and then talk on their cell phones.
I haven't stopped commuting. The pants, the boots, the accessories remain a part of my commuter outfit. Eventually, I will forget the face I already don't remember. My pace will quicken again. My boots will click obnoxiously against the late silence at Penn Station. But before the commuter does an encore, I may remember that I have change in my wallet for the guys collecting to buy a ticket. I might replace my coffee with a drink I actually like.
And then one day the memory will become part of my fictions. I will tell a story of a Good Samaritan at Penn Station. It will lose its brevity because time elongates all anecdotes. The baseball cap will have a color. I will add a dash of makeup to the girl's face. The double-cheeseburger will write lines for itself to say.