This evening, I was cycling down Leland Avenue, heading towards my turn onto Loop South, when I came upon two young woman walking towards me in the road. As I closed in on them, I heard one of them remark to her friend that something – unheard by me – had been 'an interesting experience'.

She spoke the phrase in a half-condescending, half-sarcastic tone of voice. Before I could hear anymore, I was already far behind them and out of earshot.

I spent much of the rest of the journey speculating on just what this 'interesting experience' could have been? A restaurant, a lover, a tattoo, a roller-coaster ride, a college course? No way of ever knowing.

This woman will never know that her three words caused a total stranger to devote not a little attention to her life, spinning out scenarios of increasingly unlikely verisimilitude.

I wondered whether anything I ever said in a public had a similar effect on some other total stranger? I suspect it has. Such interactions fascinate me.