Regarding the snotty medical assistant. I can do and have done "snotty" right back.
Sometime they totally "overstep" acceptable boundaries.
One had the nerve to tell me that my "cancer" was slow growing.
BTW, I don't have cancer.
Recently had the same issues with a student dental hygienist who scolded me for a gum problem that I do not have.
You might learn a couple of really "polite but withering" comments that can be used in such circumstances.
Good luck.
IAS