What is it called when someone outright denies that their facial expressions carry meaning?

So my mom is this sweet lady, and what I'm saying is she is usually cheerful and doesn't have a negative demeanor. However when I bring up certain topics she can get a very angry look on her face and I ask her if she is okay and she goes back to the cheerful demeanor. For example she wants me to be on disability and when I talk about wanting to get a job a huge cloud of resentment hangs over her because I'm not following her advice. It's very frustrating because I know at times she must be upset yet has never made it known. I used to argue with her a lot because of what I thought wasn't having closure with my father, however I wonder if sub-conciously I actually wanted her to argue back because all she does is be nice and spoil me and not disiciplne me, as I said she does encourage me to get on disability instead of getting a job so there is that.