Me too! I realised that my work-load as a teacher was spilling over into my private life, and that if it continued to do so, our marriage would suffer.
Then my head-mistress told me I could not refuse to correct a sixteen year old boy's essay that had been handed in too late.
I explained as I had explained to the boy's mother who had complained to me that all my sixteen year olds knew and had accepted that the essay topics were posted at the beginning of term and it was up to them to decide when to write the five essays, but that they would only be corrected if I received them on or before the due date. I told them, they were old enough to start planning their work and accepting the responsibility of getting in done in time.
I also asked my head-mistress why it was unacceptable to refuse to correct an English essay that was handed in late, when the entire Maths dept. refused to correct end of the month projects that came in late, and no-one had told them they could not do this.
As I received no satisfactory explanation, but was told I had to correct the essay, I went home, discussed the matter with my husband and a couple of days later handed in my resignination, stating plainly why I was resigning.
I have never regretted doing so.
Politically it is fashionable to try to encourage all retirees to go back to work - all countries are trying this right now, saying that there is a shortage of workers in all branches.
How this can possibly be the case when millions of young people with good qualifications cannot get work, I do not know.