When I’m in, say, Phoenix - with its gorgeous weather, scenery and acre upon acre of beautiful parks and gardens - I generally hop in the car to get from the coffee counter, to the barber shop, to the movie theater, because things are spread out and it’s easier to drive. When in Manhattan - which I find to be crowded, noisy and, compared to the paradises in Arizona, quite dirty - I invariably walk, sometimes 20 or 30 blocks at a time. Researchers at Stanford University, never at a loss to coin a term, have labeled this difference among cities “activity inequality.”