Well, I do have reactions to some of that as well. I have been called 'luv' in some shops in the UK and did not find it offensive. I was okay with being called 'the boss' by a waitress in Ercolano, Italy, but later when a waiter in another town called me the 'the boss' I felt it was condescending and manipulative. I began to have a different point of view about the exact same term based on gender, I think. In fact, it was probably manipulative on both their parts, but the waitress referring to the female customer in a marriage as the 'boss' versus a male doing the same just felt off to me. But it was the culture, not necessarily of the entire area (it only happened in two restaurants in the Naples area, and nowhere else).
Sometimes these kinds of greetings, salutations, etc. are part of the culture of the locale, and sometimes they are part of the culture of the types of business. Sometimes they seem to be based on the ages of those involved as well as apparent pre-conceived perceptions of those using them.
From a professional standpoint, I agree, it is truly inappropriate in written correspondence. If I were to have used such language in a memo when I was a supervisor, I believe it would have been grounds for a sexual harassment case, or at the very least a reprimand from my superior.
In local stores in my own town, I find that some cashiers do use those types of endearments, while others do not. I don't like being called ma'am, but it's what's done in some parts of the country and considered a form of respect, so I do not take offense. They learned their manners from their elders and they are following what they were taught. If I'm in a store in Santa Cruz, California and someone calls me 'dude' or 'dudette' I actually love it, because I am a California gal and it makes me feel at home. For me it's about perception, I think.
When I'm in a healthcare setting, I am not offended by the endearments, not only because it is part of the culture, but also because my hair is white and healthcare professionals often tend to use endearments with the very young, the frail, the elderly, and in fact with any client who may be in a vulnerable position in order to set them at ease.