There’s an Irishman, an Englishman and a beautiful girl sitting next to each other, girl in the middle, in a train. The train goes through a tunnel and it gets completely dark. Suddenly there is a kissing sound and then a slap!
The train comes out of the tunnel. The woman and the Irishman are sitting there looking perplexed. The Englishman is bent over holding his face which is red from an apparent slap.
The Englishman is thinking “Damn it, that Irishman must have tried to kiss the girl, she thought it was me and slapped me.”
The girl is thinking, “That Englishman must have moved to kiss me, and kissed the Irishman instead and got slapped.”
The Irishman is thinking, “If this train goes through another tunnel, I can make another kissing sound and slap that Englishman again.”