I don't remember any time in my life where it ever felt normal to me to randomly talk to strangers. I went to London when I was a teenager and was made uncomfortable by how chatty the cab drivers were. Later, I worked at a startup and my boss was preternaturally gifted at chatting up strangers, which he did habitually in every setting we were in when we traveled; on the plane, on the bus from the airport, &c. I remem…
Growing up in a small Swiss village I wasn’t born in, I had to learn that you basically greeted everybody you passed in the road, under the assumption that you knew them or were supposed to know them (more conversations were not needed).
Moving to a large Swiss village, I had to learn that saying hi to random strangers was considered weird at best.
First time I visited Southern California, I was very uncomfortable with strangers striking up random conversations. Later in the trip in San Franciso, I felt that the slightly toned down form of this habit was more comfortable for me.
Moving back to Switzerland after having lived in CA for a few years, I had to relearn old habits.