I got a lift from a tourist from Boston when I was hitchhiking from Falkland to Auchtermuchty in Scotland

He had an A4 sheet of paper that his wife had taped to the front of the glove box that said “LEFT YA FUCKIN BOZO” to make sure he stayed on the right wrong side of the road

If he was from Boston, it was probably letter, not A4

I probably shouldn't upvote people just because they say the first thought that crossed my mind.