Actually, I just remembered something that I was somewhat on the receiving end of this once.
I did a vlog about egg nog a couple of years ago (it's private now, so yeah), and made a remark about some people apparently liking to mix alcohol in egg nog to make it, "Taste better", by saying there's only two kinds of people I know of who would do that: alcoholics who are looking to get buzzed, and Canadians. A Canadian guy actually repremended me for saying that, saying that he found my comment about Canadians doing that to be unnecessary... but you know what? MrsPepper, and another Canadian friend of mine told me that Canadians traditionally do mix alcohol (particularly rum) in their egg nog, which is why I made the comment in the first place, because I figured if Canadians told me Canadians do that, how could it be offensive? But then again, that's almost kind of like the time I saw this white lady go on a talk show and talk about how if the N-word is so offensive, then why would black people call (still) each other that?