Am I A Curmudgeon At 30, Or Merely Quaint?

I don't know, but Col. Cooper was a fully-fledged Old Fashioned Old Man and he said

"How did we get fouled up in this first name bit? As I sometimes feel called upon to point out: My first name is not "John," it is "Sir." People who know me well enough to call me by my first name use "Jeff." Those who use "John" are ill-mannered. I note that I share this feeling with no less than Bill Buckley, so I am in good company on the subject."

Mister David is incorrect. Brother David is correct but only applicable for teenagers who know me well, and persons older with whom I am closely acquainted. If you will call me by my given name only, you had better be a good friend to me, or share genetic sequencing with me, or I am irritated. Graciousness forbids that I make a big deal of it (except to children, for whom there is still some hope) but, even if you don't know it, you are irritating me. If you call me by my family name, you had better be a shipmate or friendly co-worker with me.

You may feel free to address me as:
Mr. (redacted)
Sir
Mr. (redacted), Sir

Anything else is presumptuous on your part. As your great-grandfather would have told you, if he were still alive to teach you good manners (which your parents and grandparents apparently failed to do).