Perhaps she was trying to get you to experience the 'pissed off feeling' right in her presence in order to trigger it and get you to verbalize it to her. It sounds like you have not told her how annoying this is to you and she may be trying to get you to realize that you allow people (her) to walk all over you without complaint. I have heard of therapists telling their patients to go get a cup of coffee for them, just to show them how easily they let people cross their boundaries. It sounds a bit deceitful to me, but on the other hand, I think the boundary lesson would be remembered more because it is actually EXPERIENCED and then discussed with the T. They would get to experience first hand exactly how much you repress/suppress your true feelings.