Being called ma’am is a mere courtesy and I have been fine with it for quite some time now, probably since my 40’s.
At almost 52, I’ve had a physical few symptoms which genuinely make me feel old.
I’m rarely called sir except by cashiers or people who are doing jobs for me; I think being called sir would be the norm in those situations for anybody who looks like an adult.
I’m often called Mr. Kelly, which is kind of odd, because it’s not my last name. I actually expect to be called mister by people younger than I, unless they’re longstanding friends of my children, in which case I don’t mind being called by my first name.
Add me to the “it’s a sign of respect, and I welcome it” crowd. I use it regularly, especially if I’m not sure how to address someone.
Has this changed? When I studied French in school, they taught us that only family and very close friends should call an adult “tu.”
Doesn’t bother me, perhaps because I live in Texas and it’s pretty common here especially in retail or customer service settings.
On the subject of calling adults by their first name, my daughter addresses my best friend as “Dude” because he thinks it’s inappropriate to call adults by their first name but feels to young to be “Mr. Lastname.” Uncle Firstname is what we would normally have her call him, but he doesn’t want anyone other than his real nieces and nephews calling him that. So “Dude” it is.
Growing up in North Carolina, I grew up saying “ma’am” and “sir” to most older people and to all customers, so it never made me feel old to get "ma’am"ed myself.
It bugs me when people pull the “don’t call me ma’am” thing. Look, lady, I’m trying to be polite. No need to get your panties in a wad.
I used to be a cop when I was in my late 20s. I got used to being called either “sir” or “pig”; neither one makes me feel old any more.
I am pushing 60, but I am seldom called “ma’am.” I think lots of people don’t look at me closely enough to see that I am an old lady. I dress kinda youngish, and I have very little grey in my hair.
I love being called “ma’am” unless it is said in a snarky tone of voice. Any opportunity to view myself as a grown-up is always welcome. I don’t like being called “dear” or “honey” or “sweetheart” by strangers, though.
So they’re supposed to introduce you as Miss (or Missus) FairyChatMom? Get over yourself.
Heh heh, me too. One guy I was seeing for a couple months worked retail and REALLY liked it when I would go to the store while he was working. Said he really enjoyed calling me Sir in public and not having it seem odd to anyone. 
Other than in that context, I hate it. Then again I’m only 31 (gah!) so maybe the time will come.
Yes, of course. Or at least, “Aunt <X>” or some other honorific.
How is instilling basic respect in children for their elders a “get over yourself” issue? 
That’s hilarious. Maybe you can fine-tune this into “Your Dudeness” 
It seems to me that the ‘get over yourself’ comment was more of a commentary on expecting other people to act in the manner you want when they seem to not even be aware of what you would prefer.
A compromise would be to either introduce yourself first in the manner you prefer, or after the parent introduces you by your first name smile and say ‘Nice to meet you friends son, please call my ms lastname.’ Note, the smile is very important in this exchange. 
I got over it when I moved to the South. Here, it’s a cultural thing. Elsewhere it may have been a judgement on the part of the speaker as to my age - it always felt that way. Probably it wasn’t a lot of the time. Getting over it is a good thing.