Three absent minded physicists were busy discussing a project on the platform, while waiting for the train.
The announcement was made, and the train finally arrived.
There was complete panic among eagerly waiting passengers as the train made its way to the platform. Passengers rushed inside the train, and the train left, however, one of the physicists was not able to catch the train in the confusion.
A passerby who saw all this came up to the physicists and told him not to worry and catch the next available train.
The physicist replied, “I am not worried for myself, but the real problem is that I was the one who was supposed to catch the train, and the two of them who went on the train, actually came to see me off”.
This joke is included in the Black Book of Jokes. You can order it from here.