4 people in the carriage of a train - an Englishman, a pretty young blonde girl, an ugly old woman and a Frenchman.
It all goes dark when the train goes through a tunnel. In the dark there's the sound of an almighty slap, and when the train emerges from the tunnel the Frenchman is rubbing his face, and there's a huge red mark on his cheek.
The old lady thinks: "I bet that Frenchman fondled the blonde in the dark and she slapped him."
The pretty young blonde thinks: "I bet the Frenchman tried to fondle me in the dark, got the old lady by mistake, and she hit him."
The Frenchman thinks: "I bet that Englishman fondled the blonde in the dark, but the blonde thought it was me and hit me."
The Englishman thinks: "I hope there's another tunnel coming up soon so I can slap that French twat again."