For Cas and Dean: who surprises the other with flowers on a random day?
Dean would, I think!
He’d try to play it off as no big deal, the flowers were practically GIVEN to him and really, what use does he have for flowers? None, so he gave them to Cas, it’s nothing, really…
And then, of course, as the relationship progresses and Dean gets more comfortable with it (and with himself), he’d start loving the hell out of bringing Cas flowers to surprise him.
“Hey, Cas, saw these and thought of you,” as he hands Cas a bouquet of blue-violet forget-me-nots, or cornflowers the color of Cas’s eyes.
“Happy anniversary, sweetheart,” with a bouquet of red roses.
“Thought you might like these,” with daisies. Sunflowers. Snapdragons.
Cas’s eyes just light up so much and he gets so excited about the flowers every time Dean brings him some. It makes Dean feel all warm and fuzzy and usually gets him sweet, soft kisses (which really, he can get any time he wants, but these feel special because Cas initiates and is just glowing with happiness).