There's nothing wrong with having high expectations. Indeed, many an Ofsted report has highlighted this as a key factor in a school's performance.
However, there is such a thing as realism. For example, I am a PE teacher with a background in competitive athletics. I was good, but I was never going to break a world record. You have to accept it.
Some parents, though, have skewed perceptions of their children's abilities. My worst parent was delusional.
His lad was a promising footballer, skilful but lazy. As a woman running the football team I suppose I was fair game for the sort of sexist nonsense that was bound to follow from some quarters.
The pupil could "turn it on" in matches when Dad was present but didn't want to know when the team started losing. His vicious streak was also well-known.
When I dropped him for a relatively big game (sense of proportion needed), Dad went ballistic and marched into school to confront me. He caught me in the corridor and went through the expletive dictionary with a fluency equalled, in a football sense, only by the Barcelona midfield.
He even turned up to the match to offer his support - to the opposition. I'd like to say that we won and he slid away in shame. But we lost. I deployed the appropriate managerial gesture and stepped aside, enlisting a male colleague to run the side. Sadly, his losing streak lasted for the next two seasons.
The writer is a teacher in East Sussex.