One in particular.
She was convinced she was my girlfriend, even though I made it explicitly clear she wasn't. She agreed we were just hooking up, and weren't a "thing". I figured if I were upfront about this, it wouldn't come back to bite me in the arse. That way, there'd be no hiding behind a pseudo-plausible excuse of having been coerced into anything.
She knew I only slept at her place on weekends I didn't get laid when I went out drinking or was otherwise unoccupied. She knew that if I didn't answer my phone, it usually meant I was getting shitfaced and trying to get with other girls. Even when I wasn't. I only contacted her when I wanted to have sex and did the minimum required to not have her disappear, but even then I was mostly taking the piss. She cooked up all kinds of outlandish things about me (and us!) to fill in the blanks. After a little while, I think she was playing herself.
She seemed to really want to believe that I was "broken" and I just needed love. Maybe she had a point, but I clearly didn't value her as a human being.
Anyway, every now and then she'd try to manipulate (lol,cute) me to see if I did really have feelings for her but was too "broken" to really be able to show my "true feelings". Or something. I think she started going on dates with other guys...which I thought was likely a good thing for her. But then she'd lead them on and come fuck me instead. How was that going to piss me off? It seemed awfully convenient. She got to go on dates or whatever with them, and then came to me for sex.
In time, she got increasingly more annoying. So I told her I really was broken and couldn't love her how she loved me. "I only want you to be happy, and you deserve to be with someone who loves and respects you. I'm sorry to say, but that just isn't me right now. I wish I could be, but I'm just not."
Maybe I laid it too thick, because a few weeks later, she was back. It's not like I lived in a gigantic city, and she was attractive, so I figured fuck it.
Alas, it wasn't to last. She showed up one night and didn't want to fuck. She just wanted to sleep over. Which really got in the way of the night's entertainment: 2 sixpacks and South Park. So I told her to piss off, but then she wouldn't leave, which really pissed me off. So I got really mean. And she still wouldn't leave. And when she did leave, she came back crying, banging on my door, begging to be let back in.
I had to pretend to call the cops. That settled it.
But before that? Yeah, I guess Stockholm Syndrome is one way to put it.
Funnily enough, I ended up growing out of that edgy shit (too much of a hassle...) and got with a smart, pretty girl right after. Proper girlfriend and everything. I think Girl 1 saw me with New Girl a few times (she'd just pop up outta nowhere) and that set her off again, and she blew up the phone of some guy I used to hang out with, and kept on asking for me. She pulled all kinds of excuses to try to talk to me, but after that, not a peep.
Well that was a trip and a half. I haven't been that guy in a real long time. If I ever go back there, it'll be a lot more toned down. At the time, I was still trying to figure things out, and was also in a pretty bad place overall.