I knew a girl with bpd once, I rejected her and she immediately hooked up with one of my friends same day. (he looked kinda like me lole (tall, long hair, kinda fat))
She had this magical ability to drag down the mood of everyone in the room whenever she was unhappy, and she was unhappy a lot, I had figured out to leave before she would poison the mood.
She would use her best friends as pillows to cry on basically every single day, she faked having cancer and amnesia and a few other things for some reason?
She was a huge weeb like me though, she called me her senior (her senpai), I can very much say that being with a bpd girl is very much not cute 85% of the time, but some of it is kinda cute, mostly not cute!