Amazing. But on the other hand, I've seen enough shoujo love interests get away with similarly insane shit, so even if this isn't exactly shoujo I guess it's par for the course.
I also like the trope of where she doesn't know how to respond until he insults the people around her, which incites a response from her. Except it's training to see how she'll handle these types of customers in the future, so unless they also happen to step on that landmine, I hope she has an actual answer prepared that time.