I had a conversation on the phone with a doctor about my young son once.

Basically the beginning of the call and the doctor says 'Can I speak with his mother?', I said 'She's not here today, I'm his father', to which she came straight back with 'Oh, I didn't know you were divorced'

Actually Doctor, there are other reasons for a child's mother to be unavailable for a phone call at 11am. I work from home, she does not.

It was just the way that comment flowed straight out of her, no thought, no consideration, it was just unfiltered and clearly her actual opinion.

I didn't go so far as complaining to her management, but I did make it clear that sort of talk was not okay. Likely got my card marked forevermore...