While checking passengers’ tickets, a train conductor said to a passenger,
“You are on the wrong train. Please transfer at the next stop.”
The conductor also said the same thing to the next passenger.
“You, too, got the wrong train. Please transfer at the next stop.”
However, the more tickets the conductor checked, the more people he found who had gotten on the wrong train. When he found that the train was full of passengers on the wrong train, one of the passengers politely asked him,
“Excuse me, conductor, but wouldn’t it be you that is on the wrong train?”
It turned out that the conductor had the wrong train.