The best race relations lessons come when you least expect them

I don't remember his face as a whole, but there are details I doubt I'll ever forget. His eyes were dark and flickering; his weathered velvet skin revealed the slightest hint of stubble around his mouth; and the muscles in his jaw clenched as he met my gaze.

But those are details, and they come later.

First, there was only a question: "Excuse me, but do you have any quarters?"

I was walking toward Boston Common with a friend on a staggeringly cold afternoon, and I didn't turn to acknowledge him. From the corner of my eye, all I could make out was the shape of a few men bundled up to ward off the cold. The one asking about quarters held what looked to be a cup.

And there was one more thing: These men were black.

This is the part of the story where I begin to flinch, and I want to stop writing. Except there's the possibility that, by facing something I consider so despicable, something I never expected to find within myself, I might learn from the experience, and might even convince others to face it within themselves as well.

It was based on these observations - the bodies huddled, the question that hung in the air, and the color of their skin - that I drew my conclusion: This man wants my money.

I was about to pass without pause; I was, after all, deep in conversation with my friend. But as we neared, something else caught my eye: The man with the "cup" seemed to be wearing a suit and polished shoes. And that caught me off guard.

As I passed, I glared as if to challenge him - to ask what a well-dressed man was doing asking for quarters on a cold Boston day. It took about five quick steps past this man before it clicked.

Wait. Stop. Rewind. Fancy suit, polished shoes, three men, a car, a ... parking meter?

A parking meter.

I stopped dead in my tracks as the sum of my miscalculation hit me. I turned around warily to see the man with the "cup" standing in shock, his hand still outstretched, as if my hostility had frozen him.

His acquaintances were snickering and exchanged knowing glances, their eyes angry as they tried to laugh off what we all knew I'd done.

I stood there for a moment, unable to approach them, ashamed by my reflexive judgment. Then I saw what the man who'd asked for the quarters was holding, and I wanted to hide.

A dollar bill. He was holding a dollar bill that would not work in a parking meter, a bill he hoped to exchange for a few quarters so that he might park his car on the street.

I shook my head - wishing I could wake myself from this somehow - and walked toward him quickly, deliberately. As I fumbled through my purse, I kept apologizing, kept looking at his face and then away, wanting him to know that, while my judgment had been blatantly racist, at least I knew it, and at least I was ashamed.

I found four quarters and put them in his hand. He tried to give me the dollar.

"No," I said, too ashamed. "I just can't. I'm sorry."

But I heard his answer, barely a whisper, as I walked away: "It's OK."

And I knew he wasn't saying I'd been forgiven, but that what seemed like the worst offense of my life was a common offense in his, and that he might have been as taken aback by my own recognition of the racism within me as I was by the discovery of it.

And so I no longer say I am not racist. I am tired of hearing it, tired of listening to the people I know - dark and light, rich and poor, young and old - convince themselves over and over that they do not harbor such judgments. And I'm tired of convincing myself that employing "politically correct" terminology somehow renders me less capable of racism, tired of ignoring my own actions, which are at times so subtle I can actually pretend they don't exist.

This is not a story of forgiveness. I am not searching for excuses or hoping for sudden change. I am determined to look these moments in the face and know them, one by one, until I can conquer each as they come.

It will not be an easy road. And it shouldn't be.

• Elizabeth Armstrong is on the Monitor staff.