Vendor: So what's your fiancee's name?
Vendor: What's his last name?
Diana: Her last name is _______.
Vendor: Oh! I'm sorry, I shouldn't have assumed.
YES. That is exactly it.
Not "Oh...." (awkward silence while she stares at the form trying to figure out what to do)
Not "Oh! OMG that's so awesome!!! I have a gay cousin. I bet you know him."
Just a simple apology, and then we moved on. THANK YOU Katherine's Catering.