For how else could her periodic outbursts of ill-temper be explained?
She was notorious for screaming at her pupils, and when my classmates and I entered Primary Three and she became our form teacher, we had a first-hand experience of this.
If there was something in an exercise book she did not like, we would know it soon enough.
Her face crunched up in anger, she would walk to the door, and toss the book dramatically over the corridor railings where it would land with a plop three storeys below.
She would then bark at the terrified pupil -- who would be close to tears by then -- to go down to retrieve it. And if it was raining, the hapless girl would return with a tattered ink-smeared book.
She had a special dislike for a particularly small-sized classmate. Once, the girl pushed the chair she was sitting on so close to the table that she could not get up.
Seeing this, the teacher marched over to her and dragged her out of the chair, noisily. Even eight-year-olds have feelings, and I remember how awkward the rest of us felt.
The teacher never assaulted any of us physically. She was not even always angry and could be quite pleasant. But her quick temper, and the melodramatic way she vented it, makes the image of her still vivid to me today.
Just as I am sure every schoolchild can recount terror teachers, so too, I imagine, can teachers recount horror students.
Friends who used to teach speak with disgust of students who disrupted lessons, cheated, fought and stole.
Recently, two episodes of questionable teacher-student behaviour hit the headlines.
Last month, a 15-year-old St Hilda's Secondary School student punched the disciplinary master after the student was told to get a haircut and proper school trousers.
And in Pei Chun Public School, a teacher slapped a 10-year-old student leaving his left eye swollen and his face bruised. The teacher said the boy was "very rebellious".
When these incidents were raised in Parliament last week, several MPs felt that the problem in schools was not so much about teachers abusing their powers, but with ill-disciplined students.
Some suggested that schools be given total leeway in disciplining what they described as today's pampered kids.
Parents, MPs said, should sign an undertaking allowing schools to punish their children for misbehaviour.
Only the most unreasonable and unenlightened parent, I think, will maintain that schools have no right whatsoever to discipline errant children.
And these, I suspect, are the sort of parents who obey their children.
After all, parents cannot be sending their children to school only because they want them to be versed in useful academic studies. Parents must, presumably, also hope that the school will mould upright citizens out of these young minds.
And, studies have shown, schools where discipline is imposed tend to produce exemplary students.
How, then, should wayward pupils be led back onto the right path? What is the most effective form of punishment?
The most common disciplinary tools are non-physical -- reprimanding, haranguing, use of sarcasm and glaring.
How effective these are depend on how they are carried out. If the teacher is too subtle about it, the sting will be lost on the child. But if he overdoes it, children are likely to either get used to it and shrug it off, or become so terrified of the teacher's sharp tongue that it will affect their concentration.
A more extreme form of discipline is corporal punishment, and this is not something all parents agree schools should mete out.
Why, they argue, should schools be accorded the right to cause physical hurt on a child? Only parents should have that privilege, they say.
However, corporal punishment has been found to be effective in deterring unruly behaviour.
What is important, then, is how it is carried out.
The Education Ministry's view of this, I feel, is correct. It says this form of discipline should be carried out only by the principal, vice-principal or designated discipline teacher.
The advantage of this is that the person will have an overview of discipline in the school. He is better able to gauge who deserves to be whacked and who does not, and the severity of the punishment.
And as the person has not been at the receiving end of the student's bad behaviour, he would be able to take a more objective view of the incident.
If one accepts the above, then the Pei Chun teacher who slapped his pupil in a fit of anger was too impetuous.
Disciplinary standards vary in schools, according to the outlook of the principal.
Some have rigid guidelines on all aspects of student life, from punctuality to the length of hair. Others are more relaxed.
I came from a convent that was not particularly strict in areas like uniform.
My friends and I used to leave open the first button of our blouse, fold our sleeves up and our socks way down, to reveal more ankle.
None of our teachers made a big fuss of this, and I do not think we grew up any worse off because of these minor displays of teenage rebelliousness.
Schools, I believe, should not place too great a store on matters like students' appearances.
Rather, the focus should be on more basic areas like ensuring students are punctual, polite, tell the truth, do not steal and do their homework.
But while I belong to the school of thought that teachers should be fairly strict, I think heavy hands must be tempered.
The teachers I remember most fondly were those who were fair, calm, and tolerant of the occasional display of tomfoolery among us.
Schools should, by all means, punish children if they are naughty, but not in a way that cause unnecessary physical harm or, more crucially, a loss of self-esteem.
That teacher I had in primary school, I am afraid, did just that. Which is why, after 20 years, I still think of her with a shudder. And this, I suppose, cannot be how teachers want to be remembered.