Having lived in the city for a few years, I've learned to walk with purpose and momentum, making little eye contact with others. I wear my "city face," as one of my friends once called it. Strangers who try to talk to you on the street probably want something from you, or could be mentally unwell; better to avoid engaging and just continue to wherever you were going.

So when someone approached me on the Millbrae BART platform today and asked me if I could help him, I gave him barely a glance before responding with my usual, automatic "Sorry, I'm not interested."

But he asked again, standing in front of me, and I was sitting on a bench, unable to escape, so I looked up at him. He was a Latino man, not big or tall, face somewhat lined, holding a hardcover book. And I saw that he was pointing at the first word of a paragraph in the book: Nevertheless.

I realized he didn't seem like a solicitor or panhandler, but I was still on guard. "Maybe I can help, what do you need?" I responded, hedging my commitment.

"What does this word mean?" he asked me.

My guard finally down, I wracked my brain trying to come up with a definition, finally returning a flimsy attempt: "It means 'however.'"

"'However,'" he repeated, considering it. He pointed at Nevertheless again. "How do you say this word?"

"Nevertheless," I pronounced for him.

"Okay, thank you," he said, and returned with his book to the other end of the bench, leaving me to sit with my shame.