Evo
Sounds like you are writing from experience
I could add a few:
Fly any walk-in trial lesson before students who have booked weeks previously.
Teach the night rating in a plane quite different from the one the student has been flying all along, because you've got only the one plane on which the blown light bulbs have ever been replaced.
When training the IMC Rating, make the student do some flights in one plane (which has ADF but no DME), others in a different plane (which has DME but no ADF) and apart from the six main dials everything is in different places between the two.
When he's got his IMC Rating, and is renting the only available plane in which a few things work, allow him to run up 50 hours' worth of self fly hire in it at £120/hr before he realises that anything that breaks will never be fixed because the owner (from whom the school rents it) has refused to spend any money on it for the last two years (but you knew all along).
Train the student for his IMCR in an unusual plane which you dispose of the day after his Rating arrives in the post (but you knew all along)
When a student's asks for your view on him spending £10k to purchase a share in a syndicate (of which you were once a member) operating a PRIVATE CofA plane, to do an IMC Rating in it as well as obviously fly afterwards, you offer a favourable opinion .....
When a student asks why the checklist asks for the avionics master switch to be turned off before the engine shutdown, tell him it is because the checklist was approved by the CAA and so he has to do what it says.