Something that may be unique to southern Ohio. On country two lane roads, when two drivers are going in opposite directions and holding on to the steering wheel with both hands, They both raise a single finger (the index finger, not the one next to it) as they pass each other. No eye contact involved. On such a drive, I told my boss about it and he didn't believe me. So he tried it, and sure enough, everyone returned the gesture. He giggled like a 3rd grader for the entire trip.