One thing that the Argentinians had not considered when launching their invasion of the Falklands Islands in 1982 was that the islanders, like good Britains, drove on the left hand side of the road.
Early in the occupation an Argentinian Armoured Personnel Carrier encountered a farmer in a Land Rover comimg from the opposite direction. The farmer obstinately refused to give way to the heavier vehicle, and eventually the soldiers had to relent.
On the next day the islanders discovered that the Argentinian authorities had painted large white arrows upon the roads during the night.