I agree that it's harmless, as a general proposition. Especially with military rank, a person who has served is entitled to the recognition - 'tho I don't insist on being addressed as "PFC."

What does irritate me is people with PhDs or whatever wanting to be addressed as "doctor." Someone called "doctor," I just assume is an MD or maybe dentist or vet. Hell, I also have a doctorate ("of Jurisprudence"), but I'm really not interested in people coming up to me and wanting to show me where their elbow hurts...

Peter