A line that sticks in your head years later...
I just sent an e-mail to a coworker and almost used the word "hopefully" but then decided against it, because every single time I hear someone use that word I remember Janine Kishi saying that "hopefully" is one of the most misused words in the English language. I don't remember exactly which book it was but it was early in the series and I think she said it to either Kristy or Mary Anne as they were trying to escape from her and get to Claudia's room.
I wonder if that was a particular pet peeve of Ann M. Martin's and this was her way of educating people about it. It worked on me! Decades have passed and I still remember that line.
Do you have anything like this, a line that has stuck in your head for years, or some fact that you learned from a BSC book?