Did she specifically say "Granite, you are wasting my time" or a more general you are wasting time? I think those are two different things. I don't mind fighting with a therapist and it is my money and so if I want to waste my time and money - it is my problem not hers. If a therapist thinks a client can waste their time - then we would, for me, have a much bigger problem because of how very deeply I believe a client cannot waste a therapist's time because they are paid for their time.

But, to take a stab at another interpretation from she is trying to get rid of you -(this attempt is based on what I have read in those books they write) - she may be saying you pick a fight with her to ward off/reaction to the feeling of shame and that it avoids looking at the shame and where it comes from (mother) and going more into that - which would be The Work ( a phrase I truly despise in relation to therapy). The threaten thing might not be that she was afraid of you because you threatened harm or scared her - but that you threaten to leave or quit when the shame gets so much and you refuse to talk about the shame itself because of how overwhelming it is.
Just a stab at looking at it a different way.