Recently I saw an article in the Sunday feature section of the local newspaper about a book called When Strangers Meet: How People You Don't Know Can Transform You. Written by Kio Stark, a writer and teacher, the book is the text of a short TED talk she gave; you can listen to it here directly.
Her basic thesis is that brief friendly interactions with strangers enrich our lives and create a better sense of community. (This is particularly valuable in a world of people who are glued to their electronic devices!)
The reason the article so delighted me was because I've been talking to strangers my whole life. I come by this habit honestly–my mother did it, my big sister does it, and I do, too.