Bit of a tangent, but feel free to skip :
I used to live in a building with about nine people - separate rooms but shared kitchen/bathroom. One day, a new person moved in across the hall from me and my flatmate. He was very friendly and chatty but I just really Did Not Like Him. I couldn't put my finger on why - he was nice and polite and funny, but I kept having random, very clear thoughts pop into my head - for example, he invited me and my flatmate over for house warming drinks, and my first thought was "I'm not going by myself and I'm not leaving flatmate there alone". Or once someone knocked at our door, and I thought it was him. As I went to answer it, without thinking I picked up a sharp knife and held it out of sight behind the door as I opened it. When I opened the door, it wasn't him and I felt a huge rush of relief. I had never felt the need to be armed when opening the door before.
My flatmate liked him and couldn't understand why I didn't. I couldn't explain it, but I just said "I don't like him and I don't trust him". I decided to give myself permission to not be his friend - I would say hi in the corridor, but I would not stay and chat, I did not invite him in and I made it clear I was not interested in friendship.
He pushed back against this HARD - and so did a lot of other people. I was made to feel that I was being rude, stuck up, unfair, cruel - all because I was civil to him but not warm. He would stage loud conversations wondering "what he had done to upset me", and seemed to feel that he had a right to my time and good opinion. It was made very difficult for me to not fall in line and allow him to dictate the terms of our interaction. It was also (I suspect) pretty gendered - flatmate and I are female, a bit younger than him and she is very attractive. He felt entitled to have us be nice to him.
I wish I had a dramatic end to this - that when he moved out we found a suitcase full of skulls under his bed or something - but in reality, he slowly revealed himself to be a pushy and annoying dickhead, and the rest of the house began to look at me with envy when I just breezed past him rather than having to stop for half an hour and listen to him.
I still don't know why I reacted so strongly to him but I'm glad I listened to my gut - it taught me that a little social awkwardness never hurt anyone, but there's part of me that still thinks he might. It was a real lesson to me in learning to back myself, and resist a lot of expectations about how women ought to be "nice" at the expense of their own comfort.