HL Mencken
There’s nothing that irritates me more as a teacher than a 9th grader offering unsolicited pedagogical advice. For example, today a freshman suggested that I not make my vocabulary quizzes cumulative, or if I felt I had to dip into previous lessons, I only go back one or two. “That way,” she said, “we’d do better on the quizzes.”
In situations like this, rather than seguing into a “best practices” mode and patiently explaining that the goal is for students to remember the word for life, not merely for a week, and that resurrecting words from earlier lists should prompt them to review words from previous lessons, I reminded the student that she merely has an 8th grade education and therefore is about as qualified to offer pedagogical advice to a 30-year veteran teacher as I am to command a nuclear submarine.
Another student countered, “But that’s her opinion, and she should be able to state it freely.”
“Well,” I said, “I think that given that I just responded to it suggests that she stated it freely. My point is merely that in the area of teaching vocabulary Euthanasia [(cough) not her real name] doesn’t know the findings of the latest studies on cognitive retention or really understands that ensuring students make high marks on vocabulary quizzes isn’t my primary goal.[1] Therefore, her offering advice in an area in which she doesn’t possess expertise might be seen by some – I-and-I for example – as arrogant.
Of course, everyone who can read and write thinks he’s capable of teaching English. Believe me, as a former Department Chair, I’ve read many a cover letter from literature lovers in mid-life funks wanting to switch careers from real estate sales to teaching Hemingway.
However, despite HL Mencken’s contention that “[t]he worst idiots, even among pedagogues, are the teachers of English,” I submit it ain’t as easy as it looks in the movies, and it gets old getting professional and philosophical advice from novices.
Perhaps next time, I’ll ask the irritant to diagram on the board one of Faulkner’s sentences from Absalom, Absalom .
Or, better yet, just go into the best practices mode.
You Do Hoodoo 
Oh, even the curmudgeonly approach takes far too much effort. My response in situations like this is always either to say, “Thanks; I’ll think about that,” and then keep on doing what I was already doing or to make the student do all the work, which results in conversations like the following (allowing for the fact that I teach subjects other than English):
ME: “Oh, okay. I’d be happy to do that, as long as we can find a good way for me to make sure you don’t just study the weekly vocabulary but actually remember all the words you learn. Do you have any ideas about how I might do that?”
STUDENT: “…”
ME: “Well, tell you what: get back to me and we’ll go from there.”
STUDENT: “…”
ME: “Okay, everybody, let’s get back to The Story of O…”
As much as I don’t dig cliches, your last line had me literally laughing out loud.