My dd is is in year 9 and had a parents evening tonight which she came along to.
When it was our turn to approach her art teacher, he had to ask dd what her name was again.
There was an instance in his class where she asked him for a fresh piece of paper and he had a go at her because he had assumed she had come in from the classroom next door and should have therefore asked her teacher 
I get in secondary school that you obviously teach many children, but he also taught her during year 7 too.
I just didn't want to listen to his report on her because he doesn't seem to have a clue who she was!