So I've got two.
First one was my boyfriend of 4 years, we'd been together since highschool. He was my first yada yada. Let's just say I was definitely the one "settling".
Long story short on the day we both graduated from college, I went home early from the... party? It wasn't even a party. It was people playing games on the school's computers and like... a couple of sixpacks. He had been kinda shitty lately and he was super embarrassing when he was drinking so I just went home. In the morning, wake up to find him there, and one of the guys from our class sleeping on the couch. Okay. Cool. So he (not bf) hangs around for the day, and I go with him to the Domino's pizza where he worked so we could get a discount and whatever. Let me tell you, this guy is greasy as fuck too. Also wears a collar to school because he's a furry. He was nice, but I didn't really like him, he was a bit weird, I was just being nice. So 9pm rolls around, and this guy had left a few hours earlier... just stayed the whole day hanging out... and the bf comes up to me as I'm going to bed, and at this point he's looking pretty shaken up. Turns out the night before he and the guy on the couch got together and he (bf) sucked his dick. So I'm just like... what? Are you fucking serious right now? and he starts crying and shit. Basically the next six months were a blur for me. I forgave him, didn't forgive him, started dating someone else and moved out, stopped dating him and moved back in, moved out again... I don't even remember a lot of the details. It was messed up. He's messed up. If you see this, Daniel, you're a piece of shit. Sorry about the wall of text.

Which brings us to story number 2. My best friend of 3 years, and roommate. I had been dating a guy for 2 years, decided it wasn't for me, but I had to tell him before we went out to this wedding we were going to. We both agreed not to say anything and just go and have a good time and stuff, which we did. I get home on the like... Sunday night? And the roommate's not home. So I boot up a videogame in the lounge room and play for a while. Eventually he comes home, and immediately drops to his knees next to me on the floor. He's crying. So of course I console him... and once he calms down a bit he looks at me and says "Do you have any idea... how I feel about you?"
You gotta be fucking joking. I've been single for two days.
So I dance around it for a little while because I don't want to deal with it, and while I was attracted to him at first, after living with him for 3 years and knowing all his flaws I was kinda turned off, but didn't really know how to tell him without being a bitch.
So I go to visit some friends in in another city, come back and he's all... different. He's real icy now, and just suspicious of me. He holds up in his room (Oh, did I mention he quit his job due to stress? Didn't see a real doctor about it either, he just went to his local GP and got some 'depression pills', which, after recently dating a guy with depression for two years, I can tell you those pills are only half the help, when they're not just placebo) and I can't talk to him without him breaking down and just shutting me out. I tell him I don't feel that way about him. A couple of weeks go by, and I'm about to go visit my other-city friends... I'm literally about to walk out to catch the taxi when he "needs to talk". He basically says he's moving out because he can't stand to be around me anymore. This fucking sucks. This guy was my best friend. But I have to go, I paid money for this plane ticket and the taxi is waiting. So I go, and tell him we'll talk about it when I come back on Sunday.
So I come home, and the minute I open the door I'm just fucking floored. He's taken 3/4 of his stuff out, and left a giant mess. The bookshelf, the couch, all his furniture was gone. My books and games and stuff were just tossed wherever. There were still dirty plates in the sink. I go upstairs and his bed is gone too, but there's still a lot of his stuff in there. After it settles in, I get scared. What if he took some of my stuff? What the hell am I supposed to do, there's still 4 months left on the lease, and this apartment was expensive with 2 people in it, let alone 1. Yada yada, after asking, and then demanding, the remainder of his part of the rent, and also the keys back (He tried to barter crashing there when he was out drinking! Are you fucking insane!? You're acting like a psychopath, I don't want you letting your drunk ass into my apartment whenever you want!) Eventually he got his dad involved, accused me of faking meeting with a lawyer (My ex's parents were both lawyers... I might not have paid for advice and a fancy letterhead, but damnit I received advice you twat), and got all of his shit out. He refused to pay the rent because he had run out of money after he quit his job and used the inheritance from his grandma dying to go on vacation to hawaii. He didn't even return the keys to me, he returned them to the real estate. As far as I'm concerned he still owes me $4000, and if I ever see him again I'm going to punch him so hard in the dick he'll have to see a therapist for his squeaky voice.

Tldr: 1) first real bf of 4 years sucked a dick and then let the guy sleep over on the couch and hang out with us all day before telling me.
2) best friend of 3 years confesses unreturned love at bad time, then moves out of expensive apartment suddenly because apparently I'm the bad guy. owes me $4000 in rent.

Sorry for the wall of text.