Dean loves him. He knows he does. And it eats at him. Sits impatiently on his tongue. Presses against his stubborn lips.
He comes close to telling him after a particularly close call with a revenant in Toledo. But he flutters off to take care of some celestial crisis almost immediately after knitting Dean's abdomen back together.
He considers voicing his feelings on New Year's, before that feeling of promise and hope brought on by making it to another year is diminished by the realization that they have to make it through this one too. But Cas has consumed significantly more of the tequila shots that loosened Dean's lips, and when he loses consciousness a little after the midnight, Dean's liquid courage is left all dressed up with no place to go.
When it happens, it's over coffee and donuts in the Impala on a stakeout in front of a Biggerson's in Greendale, Virginia at four thirty in the morning.
"I love you," Dean finally blurts.
Castiel regards him with an expression blank as ever and Dean swallows as he replies, "Thank you. Kreme filled?"
Dean looks to the donut in the angel's outstretched hand and back at Castiel.
It takes him a long moment to decide.
"Sure." He takes the proffered pastry and turns back to pretend to watch the restaurant.
He's never tasted a donut so damn bitter.