My former roommate.
She lacked self awareness and never understood why people kept leaving her, always rationalizing it to somehow be their fault when everyone cut ties with her because she was insufferable to be around.
She was a compulsive liar. Always pretended to be interested in things people she met were into in order to befriend them. She tried to lie and say she played dota when I started playing for example and couldn't name a single hero. She seemed to assume if you put enough kindness and things in common tokens into a person they'd be your friend forever, even once you dropped the persona and started acting horrible.
She was terribly unclean. In the last month of our lease, I had takeaways nearly every night because I couldn't stand to be in our kitchen. She always made a huge mess which she'd only clean when she ran out of dishes, only to make another huge mess. There were always dishes with caked on pasta left for days at a time. She moved out without saying or cleaning a thing (she even left week old dishes in the sink) and I had to deal with it (student accommodation, basically when you move out it's your job to clean and if you don't they pay professional cleaners and it comes out of your bond.)
She tried to veto who was allowed in our apartment and would essentially throw a tantrum when I had certain friends over (who never talked/did anything to her). She constantly threatened to report me to the RA's (no guests after 10 without a pass) and would come in yelling at them to leave at 10 on the dot, like she was sitting around miserably waiting for that time, all while we sat quietly in my bedroom and didn't engage with her at all. I only had friends over about twice a month because of this (on top of not wanting to be around her mess), but that still wasn't good enough for her.
She'd also constantly pick fights with people/say or do horrible things and then pretend like it never happened the next day. One example being when I left a note asking her to do her dishes so I could clean the kitchen for room inspection when I got home. She ripped the note up, scattered it on the floor and pretend she never got it.
Anyway I've always felt sorry for her because she's a deeply miserable person and because of the whole faking personalities to impress people thing I feel like she kind of doesn't actually have a personality underneath all that crap. We were childhood friends, this has never changed. I don't think she'll ever really be happy because she refuses to accept she's the problem and because of that everyone eventually gets sick of her shit and leaves. I've seen it happen to her so many times, every time it's somehow their fault.