You don't realize how ingrained the culture is (or how you've become accustomed to rude, "privileged people" behavior) until you travel outside the zone. We flew to western Montana years ago to visit friends. While driving from airport to friends' house in a rental car people waved at us, sometimes the whole time they passed. It was car after car coming the opposite direction (far less traffic than here, but still four or more cars in a row did this). Being from the DC Area, we pulled to the side of the road and checked the car but couldn't find anything wrong that would cause all this attention. Upon arrival we told our friends about our confusion and they laughed at us. They said "In Montana, a hand signal from another vehicle is a wave. People wave a friendly hello to everyone they pass. It's not the same hand signal they use in your area."
OH! So, around here we see lots and lots of "birds" and very few friendly waves.
So as you travel, aim for the places where everyone smiles and waves... and if you're in the DC area and several people wave, you either left your coffee cup on top of the car or there is a cop around the corner. Sometimes I smile and wave at random people just to mess with their heads.
