I've always hated my first name and have opted to be known by my surname since I was a teen. It's a surname that sounds like a first name.
There's a new transfer in my department at work. A few days ago, the new transfer found out that the name I go by is not actually my first name.
Her: Oh that's interesting. Why don't you go by first name?
Me: Oh I really hate first name, been going by last name since I was a teen.
Her: That (referring to my first name) is my daughter's name.
She's been cold to me since then! We usually have a long chat in the pantry in the morning before work but she now leaves when I enter. She's also less friendly (still professional though) than before. I wouldn't have said anything if I'd known her daughter has the same name as me but what's done is done. Would what I said really offend you?
YABU — This would offend me
YANBU — I wouldn't be offended