Sam, who had been subject to Dean's classic but very limited taste in music for his entire life, could easily have written down the two-hundred or so songs that Dean loved most. To annoy him, Dean would sing certain favorites while Sam tried his best to doze off in the passenger seat. He rarely did. Those two-hundred or so songs were branded into his memory. Sam knew that weird Dean playlist front to back. So one day, midway through an investigation in a podunk town in the middle of freaking nowhere, Sam's ears perk up to Dean's deep hum carrying a tune that was somehow not on Dean's top-200-things-that-came-out-before-1980."
Sam stares at his brother in his periphery. The bleak Oklahoma landscape darts by as Dean quietly kept the tune. Sam opens his mouth to speak, but stops himself before he says anything. Sam knows he's heard this song. Where? Suddenly, it dawns on him. He bites his lip hard to keep from laughing. It was true, while they were between jobs, Sam enjoyed surfing the internet, a habit he had developed in college. There was no mistaking it. This song that Dean sang was on the top ten of the year. It was RECENT. It was terrible. Sam continues to watch in horror as Dean's lips purse. Carrying the tune perfectly.
"Hey, hmm hmm hmm hmmm," Dean breathes in an undertone, as Sam continues watching. "And this is hmmmm hm," Sam inhales. "But here's my hmm hmm." Sam fidgets in his seat. "So call me hmm hmm," Dean finishes, tapping his knuckles on the wheel as the wheat fields rush by out the window of the impala.
"What, uh," Sam asks, amused and smug and on the verge of hysterical laughter. "What are you humming?"
Dean glances at his brother. "What?"
"You were humming," Sam replies. "What song was that?"
"I don't know," Dean replies, the color draining from his face. "I was making it up."
"Alright, Carly Rae," Sam replies, unable to keep a cap on his sass.
"What did you call me?" Dean breathes, pressing his foot on the gas harder.
"Just own up!" Sam jokes, laughing outright now. "I threw a wish in the well," Sam sings in the highest pitch he can manage. "Don't ask Dean, he'll never tell."
"Will you shut your mouth?" Dean growls, nostrils flaring. "I just got it stuck in my head, OK?"
"Hello," a gravelly voice says in the back seat. Sam snaps his head around.
"Cas?" Dean asks, cheeks flushing visibly as he continues to drive.
"Am I interrupting something?" the angel asks.
"Nooo," Sam replies, grinning ear to ear. "What's up, Cas?"
"I was just… going to offer some insight into the investigation," Cas replies, eyeing Dean, who is slumped in his seat and approaching 90 miles per hour.
"Listen," Sam says. "It's hard for Dean to look right… at you, Castiel, when he's driving, but you have his number, right? So call him, maybe."
"Excuse me?" Cas asks, eyebrows knitting together.
"Oh my god," Dean mutters in an undertone.
"While I have no intention of calling Dean on the telephone, the truth is, I missed you so bad," Cas deadpans. Both brothers raise their eyebrows. The back seat is suddenly empty.