Sydney is a city built around its harbor — five million people living in close proximity to beaches, ferries, and weekend coffee culture. The pace is unhurried by global megacity standards, which makes it easier than usual to actually notice the strangers around you.
Australian culture rewards being a good mate to people you barely know. Sydney's bus drivers, surf lifesavers, and cafe regulars already do dozens of small kindnesses a day — a token chain is just a way of making the pattern visible.