Dealing With Client Attitudes

I have been a Personal Trainer for 7 years and have dealt with all sorts of clients, but there’s a new client I picked up a couple of weeks ago that seems to get sort of aggravated during our sessions. She never complains about the exercises i have her do, but seems to get frustrated and cranky as she performs the exercises. She told me she wants me to push her hard and wants to feel like she has to crawl out of the gym after sessions but It’s almost like the challenge of the exercises, which are circuit-training based and core engaging (she wants to lose weight), get to her so much that she feels like she has to show her emotions. Again, she has never complained or whined about not doing an exercise; she just gets cranky and frustrated at herself, it seems. What should I do? Should I ignore her emotions and continue to push her hard, which her and I know she needs in order to lose weight?