No matter what kind of a teaching diploma you get, whether it's a first-class honour or you just scrape through, and even if you write the greatest thesis since John Dewey, there's no question about it. The greatest influence on every teacher that has ever lived has been his or her own schooldays.
For me personally, this has meant a constant unconscious reference to my old maths teacher.
Believe it or, there was a time when E Grade struggled with a thing called algebra, and then in the Christmas of my second year in the beloved alma mater, I miraculously scored 60pc in the exam.
This meant that my maths teacher, a polo neck- and jeans-clad '70s dude called Mr Burdon, my favourite teacher, could finally take me off his intensive care list.
From the following January, convinced of my new-found genius status, I paid scant attention to all those squiggles Burdon was putting on the board.
The odd time that he did check to see that I understood, I either bluffed my way through with a "well, let me see. . ." or shrugged until he got fed up and hissed, "Jaysus, Grade, would you wake up?" and moved on to somebody else.
He was so cool with his uninhibited frustration, his long hair -- but what really crowned him as The Man was the fact that we all knew that he'd fallen off a wall blind drunk and broken a leg celebrating after Ireland had qualified for the World Cup.
Then that Easter I got a miserable and fully deserved 14pc in my maths test.
When I'm teaching and a moral issue crops up, I would ask myself "What would Burdon do?"
But last September, there was a New Kid in Town. Not a teacher, but a pupil who arrived on a transfer from the old school, all the way from my home town.
How we laughed when we realised our shared heritage, sharing memories of the staff in the old place -- especially the crazy science master, Mr Spratt, with his daft science teacher accent (a cross between Senator David Norris and the astronomer Patrick Moore) and his trousers that always sagged to display the waistband of his jockeys.
Spratt's complete lack of patience and his unpredictability was terrifying and, like this new boy, I was a nervous wreck in his class because when I started in secondary, I knew absolutely zilch about science. He picked on me for three whole years.
We both agree, however, that Spratt possessed the ability to tyrannise the most dopey of us into getting at least a B1 in the Junior Cert.
I now realise that the man was brilliant and, from now on, my aim is to emulate the apparently insane Mr Spratt, and his selfless preoccupation with making sure his pupils get even the tiniest detail right.