Being able and willing to talk to strangers unlocks the eventuality that you will one day start chatting with a person who also does that and it will be like the small talk singularity. Once a man approached me and complemented my bicycle, and I engaged with him, and since we were both waiting at the same breakfast counter without anyone else, we sat down at a table and had breakfast together, and an hour later I could have counted him as a friend. Uncommon, but exhilarating possibility.