A novice was trying to fix a broken Lisp machine by turning the power off and on.
Knight, seeing what the student was doing, spoke sternly: "You cannot fix a machine by just power-cycling it with no understanding of what is going wrong."

Knight turned the machine off and on.

The machine worked.

@kitredgrave I've done this so many times.
@KitRedgrave I'm tickled these are still floating around. Was kind of an obscure in joke when I first heard, probably back in mid 80's. I went to a talk by Knight once, good IIRC, but I was not enlightened.