Reading books about urban sociology on the bus in Guadeloupe made me think about this quote by Georg Simmel:

"Before the development of buses, railroads, and trams in the nineteenth century, people had never been in a position of having to look at one another for long minutes or even hours without speaking to one anothe"

Georg Simmel, Soziologie: Untersuchungen Über Die Formen Der Vergesellschaftung (Berlin: Duncker & Humblot, 1958), 486