Disclaimer: I don't own Supernatural. If I did, we'd have lots of episodes about the Winchester family having fun together and enjoying life. Luckily other, more sadistic hands retain creative control of the franchise.

Here's a simplification of everything I'm goin' through:
You plus me is bad news.

- "Love on the Rocks", by Sarah Bareilles

He never thought he'd say it, but Dean missed being able to bicker with his brother. Back before their lives had gotten ten times as complicated (before he'd been sent to hell, before he'd believed in angels, before Sam had gotten a taste for demon blood, before all that crap), they'd bickered all the time. They would tie into each other over stupid shit like who drove the Impala or who used the computer, and they'd go at it for a good fifteen minutes, at least. Then something would interrupt them, and all would be forgotten in the presence of more pressing matters.

Now, when they pissed each other off, they held their tongues. They were afraid of what might happen if they started to fight; they had too much ammunition against each other. It was too easy to escalate from a petty disagreement to blurting out accusations that couldn't be taken back, too easy to wound the other to the core without throwing a punch, too easy to break the uncertain and uneasy trust they'd slowly rebuilt. Too much of everything.

Dean knew they were both guilty of huge transgressions. He had started it when he made a deal for Sam's life, something he'd hated Dad for doing to him. Then Sam had started buying into Ruby's lies, while meanwhile Dean was in hell, jumpstarting the apocalypse. And the list went on. When it came down to it, Dean had decided that he was the most responsible for the end of the world, because he'd always been responsible for Sam as well as himself. But for the rift between them, the sense of betrayal and hurt – when he added up the numbers, Sam always came off looking like the guiltier party. Dean didn't just think it, he felt it, deep in his heart. The lies, the deception, the addiction…. Say what you would about Dean, he'd always been as honest with Sam as he was with himself. Whether or not that was very honest was a different matter altogether.

And now, all the little things they didn't fight over were piling up, like an invisible wall between them made of things we don't talk about, and pretty soon they were barely talking at all. But all that was about to change.

It started when Dean turned on the television. Sam was across the room, researching on his laptop; his gaze flickered up to the TV momentarily. "Could you turn that down?" he asked Dean.

Dean turned it down a couple clicks.

A second later, Sam spoke again. "That's still too loud."

Dean wasn't sure why, but Sammy's tone was really pissing him off. "I'm trying to watch a show," he barked.

Sam closed his laptop. "I'm trying to research," he snapped. "Or have you forgotten what we came here for?"

All Dean's pent-up irritation and annoyance came bubbling up to the surface. "Oh, so now I'm the one with the screwed-up priorities?" he retorted angrily, standing up.

Sam stood up in response, irritating Dean further with his stupid tallness. "I don't know what your problem is today, but get off my case," Sam said in a low tone.

"No, see, the last time I did that, you started sucking down demon blood and unleashing hell on earth," Dean bit back, surprising even himself with the venom in his voice.

Sam clenched his teeth. "Well, I seem to remember that you had some hand in the matter. In fact, you were the one who made it all possible. And I'm not talking about the torture, Dean, because that I can understand. I'm talking about the fact that you were in hell in the first place."

Okay, that was it. Dean was losing the last vestiges of his temper; he could feel his blood running hotter, faster.

"Ladies and gentlemen, this apocalypse was brought to you by Dean Winchester: the brand you trust," Sam went on sarcastically. "If you like undermining everything you've ever stood for, always use a Winchester."

"You were dead, Sammy," Dean spat, livid. "What the hell was I supposed to do?"

They stood frozen for a split second, locked in a heated glare, the tension in the room palpable.

Dean wasn't sure who threw the first punch, but the next thing he knew they were grappling on the motel floor, each trying their hardest to beat the living daylights out of the other.