Hah! I come from Ireland where the custom is also a brief flash of the emergency indicators to say "thanks". I then moved to New Zealand where they toot the horn to say thanks. I was most confused when I got tooted (rude in Ireland) for letting someone pass easily. I was like * buddy ;) then I realized what was going on, well, eventually anyway :)
Ha. In Boston I used to get frustrated at oncoming drivers flashing their lights at me. What was I doing wrong? Are my headlights misaligned? Is something falling off? Do I know you?
Eventually I worked it out: they were warning me of a police cruiser ahead.
In a state known for Massholes it’s surprisingly unjerkish.
