When you drive over the border from Ireland into Northern Ireland, there's a big sign warning you that speed limits are now in miles per hour. When you drive from Northern Ireland into Ireland, there's a big sign in English, French, and German warning you to drive on the left.
I can't figure out whether this is an incredibly subtle and clever put-down or just the stupidest damn thing on the planet.
Of course, there is the possibility that the road planners of Ireland actually run a competition for Stupidest Road Sign Ever — it would explain a lot — and this is the winner.