Forbes just put together an excellent package on the 21st century city, including my editorial about the future of urban surveillance, called "Snitchtown":
The key to living in a city and peacefully co-existing as a social animal in tight quarters is to set a delicate balance of seeing and not seeing. You take care not to step on the heels of the woman in front of you on the way out of the subway, and you might take passing note of her most excellent handbag. But you don't make eye contact and exchange a nod. Or even if you do, you make sure that it's as fleeting as it can be.
Checking your mirrors is good practice even in stopped traffic, but staring and pointing at the schmuck next to you who's got his finger so far up his nostril he's in danger of lobotomizing himself is bad form–worse form that picking your nose, even.
I once asked a Japanese friend to explain why so many people on the Tokyo subway wore surgical masks. Are they extreme germophobes? Conscientious folks getting over a cold? Oh, yes, he said, yes, of course, but that's only the rubric. The real reason to wear the mask is to spare others the discomfort of seeing your facial expression, to make your face into a disengaged, unreadable blank–to spare others the discomfort of firing up their mirror neurons in order to model your mood based on your outward expression. To make it possible to see without seeing.
