Every English teacher, when they tell strangers what they do, has gotten this reaction: "Oh, I guess I'll have to watch my grammar around you." One time, when I told someone I had a Ph.D. in English, she politely inquired what I studied in such a program: "Was it a bunch of grammar and stuff?" Clearly, to some people, a student of English is someone who obsesses about the particularities of an arbitrary system of rules governing our use of language, and who is a self-appointed enforcer of said rules. The irony is that English departments are full of people who worry that grammar rules are a patriarchal sledgehammer used to oppress those who speak and write in non-dominant dialects of English.
Don't get me wrong. We need a common language and agreed-upon set of rules in order to be able to communicate complex messages to each other. What we call grammatical, standard English--the dialect taught in schools and used in formal discourse--is that common language for many people. What bothers me are people who act like "Standard English" is the one right way to speak and write English. Many dialects of English have their own internal logic. In the mountains where some of my family lives, young people are "y'uns," and double negatives are perfectly fine. So, yes, if you ask, I will edit your paper into perfect Standard English. But never, never will I try to edit you mid-story at a family reunion.
Please share your stories of having someone correct your grammar, of correcting another person's grammar, or of leaving it uncorrected. Where and when do you think "Standard English" should be enforced?