I used to be a commuter. I wouldn't always get the same train to and from the city, but usually any train within the spread of the rush hours.
Over time, of course, the faces of fellow passengers would become familiar. Then you would notice groups of people, by which I mean those who would have conversations during the journey, people who seemed to know each other in other hours.
Some people always travelled alone, though this did prevent the exchange of the occasional smile or nod.
Then it became obvious that you could, at a push, remember the sound of voices, or some of the patterns that relationships seemed to possess.
Snippets of conversations, displays of emotions, usual styles of dress… all offering possibilities for joining in. And sometimes you did join in.
Sometimes you even learned their names.
But I am no longer a commuter; and when I do make those journeys there are new faces who do not know mine. I am free but confused by this trick of time.