My mother was an English teacher. She corrected my usage all the time. It taught me to say and write short sentences. Really short ones. Short. (I know, Mom: fragments.)
Later, teaching at WRA, I had a dear friend and colleague, Mac (James McClelland), who assumed that role. In fact, at the local coffee shop cum drug store the owners kept a Webster's unabridged behind the counter to resolve our disputes--our logomachies and grammar wars! When I would send forth a solecism into the coffee-shop air, Mac would look at me with sad disappointment and say, "I believe you meant ... [whatever it was]."
(Meanwhile, my mother, 92, has never stopped--though her technique has become more crudely subtle. Instead of stopping me in mid-sentence and correcting me, she will repeat a close version of the locution I just abused--but in Standard English--making sure she utters the key words in italics. "You want to be disinterested, don't you?")
Are you surprised that I stuttered badly throughout elementary and junior high? I figured if I stuttered, you know, maybe they'd correct me before I got too far along in the sentence ... save everyone some time.
It wasn't until I started teaching grammar and usage myself that I started having epiphanies every five minutes.
QUESTION: Whom do you think is our greatest living writer?
O'HARA: That word should be who, not whom. Nominative case. (An Artist Is His Own Fault, 204)
And that's his entire answer.
As I've written here before, O'Hara had some "issues." A delightful mixture of an inferiority complex and a towering ego.
In my last decades in the classroom, I never corrected a student's oral usage, not in front of the class--there are better ways to handle such things. (Our feelings about our language, like our bodies, are most tender. There is not much difference between correcting a who-whom problem in front of the class that noting that a student has gotten fat lately--and you didn't have that pimple on your nose yesterday, did you? It's really bright today!)
Joyce and I correct each other all the time (lovingly, of course), and we always preface it with Mac's locution: "I believe you meant ...."
Sometimes, it pisses me off, you know?
Dyer's Books on Amazon