Undue Familiarity

[Brian37]

Yes.  But more because I had told the first person NOT to call me by my first name, and he continued to do so.

Boru

The complain't isn't that they used your first name. The real problem is they continued to annoy you by not addressing you the way you wanted. 

Not everyone cares, and some people don't mind you using their first name. 

I could care less if a clerk calls me Brian, I would get pissed if they repeatedly called me "Bri". 

But, my last name continually gets an "s" added to the end of it, that annoys me too. 

Even with new people you meet outside a business setting. It is simply polite to address the other in the manor they request. 

I get that you were annoyed though.