Continuing this thought--I recall a person here in Texas telling me, "Our new neighbors are rude! They drove past our pick-up truck and didn't wave." In fact, several hundred miles west of our home here in East Texas--way out past Jacksboro (think "Green Frog Cafe" & Jerry Jeff Walker--actually a nice cafe except for the bugs
in the "open country" (no fences) out on the Lubbock Highway, the required custom was to raise one finger from the steering wheel when passing an all too rare other vehicle (NOT the middle one, NOT "Long Man"
. And rather than watch the edge of the bar ditch, the custom was to watch the other driver give his/her one finger wave
. Go figure--custom and climate!