I was just thinking this while doing the dishes (where all the best thoughts happen) but, if one were to transcribe literally Dean's every action around Cas, like if this were a written work and not a visual medium, then Dean's attraction / feelings toward Cas would be so much more blatant and harder to negate. Like sure, in a show certain glances and gestures are easier to miss especially with casual viewers. But if it was written? If this were a novel?
Dean's gaze flicked down to Castiel's lips, then back up to his eyes.
Dean looked at Castiel and slowly licked his lips.
Dean's pupils rapidly dilated while gazing at Castiel.
Dean walked by Cas, clapped his shoulder once, then let his touch linger.
Dean pulled out of the hug and cupped his hand to Cas's jaw, smiling softly.
Castiel stepped out of the bathroom, now looking brand spanking new. Dean covertly adjusted his pants.
LIKE. And this is all textual. These are canonic things that happen. It's not just "subtext." It's plain text. It's right there, happening in front of you. And these might not have any "intentional" meaning. But, authorial—or actorial—intent is not necessary for valid interpretation. The text stands alone. No outside explanations will change the text. If it's in there it is free to be interpreted by the audience.