People that aren't into small talk, how do you handle nosy strangers judging and asking ?

I usually freeze when I am uncomfortable or someone is inappropriate or aggressive and would like to handle this experience in a civil and kind way. I know people like this are everywhere ( hope not) but probably.

Example: Had a dentist appt. Chatting should not be part of appointments to begin with, some people like it but I do not. I had an appointment with a dentist that to begin with had a very unprofessional attitude and started asking me how much I make and how can I pay rent in such area and why do I like certain countries if it's so different ( my partner is from that country) , all this invasive rude inappropriate questions only because I answer where I live. I did not think she would go off on me talking and giving opinions uncontrollably.