Have you ever seen those videos filming London streets in the 1970s? They are absolutely packed with groups of two or three people, not going places, but just standing there, chatting, as if they have nowhere else to be. It is something most of us have never experienced in any form and the change has happened over long enough timescales that we are used to our streets of strangers just going about their lives, the external world just a physical inconvenience to traverse as quickly as possible, not the real world where one just exists.