All 19th-century writers saw teachers as too poor to be genteel. Charlotte Bronte made three heroes endure the classroom: William Crimsworth, Jane Eyre and Lucy Snowe. The Little Women pitied John Brooke for not quite being a gentleman and Ichabod Crane (Sleepy Hollow) tried to marry his way out.
Teachers have long been suspected of venting their personal frustrations on innocent pupils. Teacher (The Beano) did it with a bamboo cane while Roald Dahl's Trunchbowl used anything and anyone that came to hand.
Some teachers consider it their mission to snuff out all spontaneity and enthusiasm. Billy Bunter's Quelch and Dickens's Gradgrind believed that cramming in facts was all that mattered.
Bernard "Privet" Hedges from Please, Sir! was not the first incompetent to become a teacher. Remember Millicent Fritton of St Trinian's, Principal Seymour Skinner (The Simpsons), and the unfortunate Miss Appleyard, who lost so many girls on a picnic at Hanging Rock.
Any man who loves his subject can't be much fun in bed. While no one believes this about university lecturers, fiction has come up with a lot of sexually-repressed teachers - Crocker-Harris in The Browning Version, and Pow-Wow in To Serve Them All My Days. All marry sexier women and, in the case of Ryan's Daughter, this proves disastrous for Charles Shaughnessy.
But there are also some highly-sexed teachers out there. Not just the frustrated Mrs Krabappel from The Simpsons, but the odious Simon from Teachers and DH Lawrence's Rupert Birkin.
Alas, there are very few action-man teachers, unless you count Dr Who's companion, Ian Chesterton, who saved the world on frequent occasions, and John Kimble in Kindergarten Cop.
There are, however, many unorthodox teachers who prove inspirational. Good ones like Louanne Johnson in Dangerous Minds, dubious ones such as John Keating in Dead Poets Society, and positively dangerous ones like Miss Jean Brodie herself.
Strangely, fiction has produced very few all-knowing teachers. Only Yoda (Star Wars) and Professor Dumbledore (Harry Potter) seem infallible. And they rely on magic and mind tricks.