A student who was about to go back to his country once told me that he loved my class because I taught him something that he’d been confused about for his whole life. I expected him to say present perfect or past continuous or some big, important thing like that, but nope.
His life-changing epiphany was when I taught a mnemonic to tell the difference between the words Tuesday and Thursday:
Tuesday sounds like the number two, and it’s the second day of the week,
so Tuesday = 2-sday. So easy!
I’m sure that wasn’t a planned part of my lesson. I probably mentioned it casually when a student stumbled over one of those words in conversation. But he was really excited about it. He said that throughout all of his years of school, he’d always had trouble with the days of the week, but not anymore! Isn’t it funny when you realize that things that seem little and insignificant to you are the things that your students end up remembering the most?