Southern Hospitality- Does it work in DC?

What I have been learning is what is considered proper and etiquette in one part of the United States, may not be as obvious in other places.  I did notice when i was originally doing research to start an etiquette blog the only blogs I could find were written by and for people in the southern states.  What about people up north? Living in DC you come across such a mix of people, southerners, northerners, politicians, hipsters, etc.  Is it possible to keep them all happy? (spoiler alert:no).

I was listening to the radio and the DJ was telling a story about how he made a 30 year old lady upset by calling her ma'am, saying you only call 80 year old ma'am- oddly specific age. He said he was completely caught off guard that something like that would be upsetting. If anyone called him sir he said he would assume they were either raised in a strict house or in the military. It would never be something that offended him.  The DJ's coworker, a female in her late 20's,  said being called ma'am would have upset her.

Now if this had happened in the south, it wouldn't have even been talked about. But, here in DC it seems to be an issue.  This isn't the first time I've heard this argument.  So who is right? Personally I don't mind being called ma'am, the twice a year that it happens. Maybe because I look so young I appreciate anyone who thinks I'm over 12.  I don't see whats wrong with calling anyone ma'am as long as its done in a respectful tone. If someone is calling you ma'am or sir to get your attention, how is that being disrespectful? What would you like them to call you? "Excuse me, bitch, you seem to have dropped something." Seriously, what would an alternative be?

I think if you are truly being respectful, you can't go wrong. If that upsets someone, that's on them.