IT'S LIKE A SITCOM PLOT BUT MORE DEPRESSING.

I've been reading this site, and there was a discussion there: http://www.jimandellen.org/showmpvolch.html

I can't remember which page it was, unfortunately, but it pointed out that Mrs. Norris doesn't let Fanny talk about the play when Lady Bertram asks, and discourages attending the rehearsal. The writer read an implication that Mrs. Norris was trying to keep Lady Bertram from seeing the inappropriateness of it. Interesting, in light of the fact that Mrs. Norris runs things next to Sir Thomas, and he's trusted her with not doing this very thing.

This one is also relevant: http://www.jimandellen.or/mp/TheProblemofEdmund.html
"...he's [Edmund] just like all the Bertrams, Mrs Norris and everyone in the book but Fanny and interestingly Mary and Henry Crawford (who know themselves very well and simply aren't bothered about their amorality)."

For Henry, Mary, and Fanny, self-knowledge probably contributes to understanding how people behave around them. (Though not everything. I don't believe Mary knows of Fanny's love for Edmund, and Henry didn't either.) It's in their interest to know; how else can the Crawford's be so socially adept and Fanny get by as nearly a servant?

Fanny, the reliable worker who never does enough that she can't be asked for more. Of course that's how this kind of dynamic works. I think if it wasn't for the particulars of this situation, she wouldn't mind as much.