The song had been stuck in his head all day now.
The same lyrics over and over and over.
He knew he was beginning to piss off the two brothers, but he couldn't help it - both of them understood, but that didn't mean they had to like it.
He sung a line again, muttered under his breath, unable to stop it. No matter how conscious his brain was of it, he still managed to do it.
Dean slammed the brakes, hard, the Impala coming to a sudden halt in the middle of the empty highway.
He must have really have been angry to be so rough with his baby.
"Goddamn it, Cas, if you're gonna sing the same line from a song, over and over, at least let it be from a good one!"
After a small amount of fiddling with the console, music starts blaring from the speakers.
Dean sings along at the top of his lungs, starting driving again, and the song is catchy enough for Castiel to pick up on the lyrics. The blond plays the song again, and the pair sing along to the music, while Sam looks vaguely embarrassed to be in the same car as the pair.
He's ignored, and Dean and Cas enjoy the next couple of hours, with more songs, more singing, and more embarrassing of Sam.