I'm slightly regretting posting that I never use/used ma'am or sir.

I've never once considered myself one without manners. And I certainly have MORALS.

I'm a kind, respectful person. And was an incredibly respectful child as well. It just wasn't something common up here, in our area.
It's a bit of a broad generalization to make, to say that just because all children do not use "ma'am" they do not have manners. If I had children right now, I would not be inclined to teach them to use that word, as it is a bit foreign. But you can BET I'd instill good manners.

Absolutely!! Mr., Mrs., Please, Thank You... among others.
It must be a regional thing.