What do you think would cause my mother to dislike me so much?

My mom dislike both me and my younger sister.
She is needlessly critical of us. Whenever I wasn’t sure about what trade I wanted, she would be very rude and critical. But when I tell her what I want to do as a career (denal chairside assistant), she mocks me and tells me not to think about that job. Then proceeds to ask me again and again what I want to do. And tries to bully me into applying for a job where she works. I can’t. She would be in my face every chance she gets besides, I have a disorder that makes my body temp very low, and the place she works is very cold. Anyway, a couple days later, we were talking and watching tv. And she mocked me and saaid “how are you going to be a dental assistant if you can’t take care of your own teeth?”. She said that after seeing a piece of food on my tooth. We had just had dinner, that I made. No thanks from her.

I just got a job yesterday, and she still seem a bit dissatisfied. But not as grumpy.