This one was actually one of the milder ones, which is actually kind of scary when you think about it.
See, I lived in one apartment in a crappy apartment complex with a friend. She's still a friend, but we just didn't get along well living together. I didn't go in for being stood over while I washed dishes, and snapped at if I used one of the 5 washing tools in the wrong order. Also I was pretty messy. I'll totally admit that now.
So I moved next door.
Now, the old apartment had a couple friends living in it, and one of those friends had a friend who was often shelter-challenged. He wasn't big on being a sucker for "the man," so he didn't work very often, or have a permanent address. He ended up moving in behind the couch over there. I became friends with him as well.
I guess the first sign that he was probably not too healthy of a person to be around was when he got drunk and formatted my hard drive. I should have just removed him from my life as much as possible then, but I was really young with bad boundaries, and still a giver of endless "second chances."
I foolishly let him have a key to my place when I moved next door, for some reason. I'm not really sure why. That was a pretty big mistake, heh! Maybe I let him babysit my pet rats once.
I got some DSL going, as I actually had a pretty good job at that point. One day, coming home from work, I discovered some CAT-5 running out from under my door to the apartment next door. Yeah, that was really subtle. He got upset when I unplugged his cable from my router, too.
Of course, he also wanted to knock a hole in the wall between the two apartments, but uh, we vetoed that.
He would blast music at top volume at 3am, and when I'd go over and bang on the door, he'd yell at me about how people were trying to sleep.
One day, while I was taking a bath, he barged into the bathroom and started ranting drunkenly at me. Humiliated and scared, I started to cry, and he yelled "what? I'm not lookin' at yer titties!"
He didn't remember this the next day and cried when he found out he wasn't allowed back in my place. I fell for the crying and mistook it for real repentance, and let him in again. Totally my fault, that part, heh!
Eventually he got kicked out of the place next door, and came to me, weeping and repentant and full of "I'm not drinking any more, I just need a chance to get back on my feet, I'm a new person, it'll be different from now on, please, I can't survive out on the street!" A sucker for hard luck cases, I let him sleep on my futon in the living room. The wall alongside the space behind the couch in the apartment next door was stained almost black.
A month or so later, while I was away at work, he had a friend over. They completely trashed my apartment, his friend stole my fancy frock coat and probably some other stuff, and they were gone, off to New Orleans, when I got home.
Hidden behind the futon were a ton of empty cheap liquor bottles.
That's when I started to learn to not trust everyone or let pity dissolve my boundaries. As much. Still have to work on all that, actually!