The teacher gave the best advice he knew how to. By the time I went through that class his advice had improved to starting with telling us that story when he tried to explain what a proof was. I am not sure how many students took it to heart though.
(How do you think I heard it? :-)
If anyone is curious, this is a true story. I have changed the wording somewhat (mainly because my memory is fallible so I don't remember the original wording). I heard it from the professor's mouth, on or about the first day of my intro to real analysis class, Fall of 1990, at the University of Victoria. The professor in question was Bill Pfaffenberger.