Three professors were deep in conversation at the railway station. The train arrived, but they didn't notice until the guard shouted, "Take your seats, please!"
The professors rushed for the train. Two managed to board before it departed, but the third, Professor Egghead, was left behind, looking worried.
A student of his was also at the station and tried to comfort him. "It wasn't really bad, sir," said the student. "Two out of three caught the train. That's quite good, you know."
"I know," replied the professor. "But it was my train. My friends only came to say goodbye."