A/N: Supernatural belongs to the CW people, because if it was mine, I'd have given Sam a girlfriend and a puppy, and a house with a white fence to Cas and Dean a few seasons ago. Also, the idea for this was a post I saw in my favorite place on earth: Tumblr.

Not beta'd yet, so please forgive my mistakes.

The Window Mistake aka That time Dean fucked things up and Castiel made a friend… sorta.

There're some questions you inevitably ask yourself when you wake up before nine on a Sunday. Why me? What was on my mind when I decided to live near to a church? Why the fuck is the sun so fucking bright today? Is this some kind of karmic punishment for not feeding my pet turtle Sheldon on 4th grade? Why is there a strange shirtless man sleeping on my couch?

Sometimes questions have answers, sometimes they don't. But the last one, actually, has a simple explanation: Dean Winchester is a jackass. Don't get this in the wrong way, this is not said as an insult, but as a real empirical fact; the sky is blue, the sea is salty, water is wet and Dean Winchester is a jackass.

If Dean Winchester wasn't a jackass he wouldn't have had the brilliant idea of going out with Benny three days in a row, knowing that only one night with his friend was enough to overwhelm the alcohol in blood rate for a normal human being. If Dean Winchester wasn't a jackass, he wouldn't have ended up, for obvious reasons, so drunk that he forgets where his house keys are. If Dean Winchester wasn't a jackass, he may have thought that maybe, and just maybe, going into his brother's apartment by climbing the window at five a.m. wasn't a good idea (it's remarkable to mention that Dean's brother is a huge human being made of muscle and if Dean Winchester weren't a jackass, he would've remember that he'd kick his sorry ass for breaking into his house without a warning). If Dean Winchester wasn't a jackass, he would have realized the moment he got into his brother's home that 1. His brother doesn't have a coffee table in his living room, 2. His brother's couch is like a hundred times more uncomfortable than the one he falls asleep in and 3. His brother doesn't have cats. But since Dean Winchester is a complete jackass, he goes out with Benny three days in a row, he forgets where his car is, he jumps up in a tree to get into his brother's window and he ends in the couch of a very, very, very, confused Castiel.

The reason why Castiel is so, so, so confused (well, apart from the obvious part in which a strange shirtless man is on his couch at eight forty-two in the morning on a mid-September Sunday) is because as any other regular kid in history, he had a rebellious phase where all he would do was drink and party and, if there was enough alcohol in his body to forget the next day, have sex with some girl. But, not as any other regular kid in history, he ended up being stabbed by a girl named April, which made him drop that life and get into what one could delicately call a celibate period. But let's not pity poor Castiel for not having sex in the last three years. Not too much, at least. Because in that time he discovered a lot of things about himself, like he likes to read until he can't handle it even if he's tired and moody the next day, that he hates waking up too early, that he likes Quidditch rather than football, that he likes Han rather than Obi Wan and, the most important of them all, that he likes Luke rather than Leia (if you know what I mean). And after all this little epiphanies, another one came: Castiel enjoys loneliness. So, little by little, he became a hermit (as his brother would say); his life is reduced to go to class, go to the library, go home and –sometimes- go to Gabriel's. And back. The only actual friend he'd made in the last few years is Balthazar, who once in a while pays a visit.

But is pretty clear that the person sleeping on this couch is not Balthazar, or anyone he knows because Castiel doesn't have any more friends and he's too tall to be Gabriel. It's also pretty clear that he shouldn't be there. And Castiel wonders if there's some kind of social protocol for this situation. So he does what any real man would do if he finds another man half-naked on his couch at eight forty-two in the morning on a mid-September Sunday. Scream. Too fucking loud.

"What the…?" Dean wakes up startled (which he immediately regrets). "Who are you?"

"Who are you?"

"I asked first". Castiel didn't expect that answer. What kind of human being breaks into somebody's house and wakes up with pre-schoolish replies?

"Bu… but… this is my house".

"What?" for the first time Dean realizes that this is not his brother's couch, nor his brother's apartment. "Where am I?"

"Green Street, 437th"

"What apartment?"

"3rd floor, apartment C"

"That explains it. Also explains the cats" Castiel looks at him like he's the first human being he had ever seen. "Uuuuhhh…Sam lives upstairs". Castiel's blue –very, very, very blue, notices Dean- are still looking at him with astonishment (which, okay, is pretty damn logical). "Sam; stupidly tall and hippie hair, is my little brother and lives upstairs, I thought I was getting into his living room".

That explains a lot thinks Castiel. Of course he knows who's Sam, he have met him lots of times in the elevator and sometimes in the university, although until that moment he'd only know him as "Bitable Ass". The nickname was not given by him, but by Gabriel and Balthazar who apparently don't have better things to do with their lives than gossip about the people who live in his building. (Just as a side note, next-door neighbors were 'Hitler-moustache-like Bangs' and 'Too Colorful Clothes'; downstairs were 'Ellen Denegeres and Ken Doll Bastard Son', 'Future President of the United States', 'Horse-like laugh' and 'Too Gay Even For Cassie'; Hael and Judith used to live across the hall, but Balthazar had sex with both of them and they moved out, so they were substituted by 'Wow Big Boobs', 'Blonde Not That Blonde' and 'The One Who's Always Singing').

"How did you get in?"

"There's a tree strategically well situated under your window and, by the way, you should put a better lock"

"Sure, it's just I never considered that someone was crazy enough to jump up the tree to sleep on my couch" Dean laughs, and although he immediately feels like his head is about to explode, it totally worth it. Castiel then takes his time to look at the man he's talking; he notices the little wrinkles on the corners of his eyes when he laughs, he notices the little freckles on his nose, he notices he has the greenest eyes he have ever seen in his life and he also notices that even he's, most probably, hungover he's really attractive. Maybe attractive isn't the right word. Handsome. Painfully handsome. So handsome that it should be illegal to be that handsome.

"Well, dude, I'm really sorry. I promise not get into your house at night ever again". Castiel, whose life felt so incredible boring right now, suddenly though it was unacceptable not to have more strangers coming in through his window at night. "I'm Dean, by the way. Dean Winchester".

"Castiel Novak"

"Nice to meet you, Castiel. Again, I'm so sorry. Now I'll go to wake up my little bro so I can eat everything he has in the kitchen… Where's my shirt? Never mind. Bye".

Castiel stands there in shock.

"Hey, Cas." Dean looks at him smirking "want a coffee? I mean, not right now, I feel like I was hit by a train, but… Some other day." Dean may be a jackass but at least he knows he should compensate the poor kid who let him sleep in his couch (even if he didn't know) and whose eyes are as blue as the sea on a calm day –the fuck? Okay, he needs to sleep like right now-. Honestly his brain isn't exactly working, so he speaks before he has second thoughts about it. But Cas nods, so everything is fine. "Cool. See ya then. And Cas… Nice mole." Before Castiel realizes he's talking about the mole next to his right nipple and, ergo, he has been shirtless this whole time, and furthermore blushes so hard that he looks like a giant tomato, Dean-I'm-too-attractive-to-go-out-without-a-warning-sign-on is gone.

Dean knows he need to rest and Cas thinks he won't be able to sleep for a while. Cas realizes he doesn't have his number or any other way to get in touch with him and Dean thinks that if fate made him get into the wrong window, it certainly will make them see each other again.