My Motson moment happened during the last time that I led a school assembly. I have not been asked to present one since.
In an attempt to illustrate the great heights my audience could reach with self-belief, practice, commitment and willpower, I had decided to illustrate my message with a frame-by-frame video of the previous evening's Olympic 100 metres final when the gold medallist had smashed the world record.
Unfortunately, the role model I chose was sprinter Ben Johnson. Within minutes of my assembly ending (Whitney Houston's Olympic anthem "One Moment in Time" was still hollering across the school) news spread through the staffroom that he had just failed a drugs test.
Soon Johnson was on his way home, disgraced and humiliated.
He was not the only one.
I was consoled by a pupil: "Don't worry Mr Petty. Hardly anyone was listening to you anyway."
How many assembly speakers felt similarly betrayed by the World Cup?
Any head who highlighted the tournament's themes of global friendship and anti-racism now knows that the only truly lasting image from the tournament is of a Frenchman butting an Italian for alleged racial abuse.
Would an assembly linking the world's top footballers with the school's new healthy eating or healthy lifestyle initiative prove to have been more fruitful? Afraid not. Subsequent scenes of the player of the tournament puffing on a fag and of "Roly-poly Ronaldo" breaking the all-time goal-scoring record were definitely not what the doctor ordered.
And those who opted for the "metatarsal assembly" have probably now resigned. "Brave Wayne is so determined to get his poorly foot better in time. We can all learn from that." Yes, indeed. It recovered just in time for it to land in a Portuguese groin and for Wayne's Year 9 classmate, Christiano Ronaldo, then to sneak on him to the teacher to ensure a suspension.
So many of these "heroes" were simply difficult children on a bad day - lying, cheating, sneaking, swearing and routinely insulting each other's mothers. And the winning country? Italia - the World Cup godfathers. In some sense I feel we have all been relegated.