First at Dean,
It tells you a story of change.
Look how it went from looking at Castiel, a creature of celestial intent, a dick with wings, with contempt and distrust and how it turned into worry and nervousness about Cas, your friend, the one who did it all for you, who may have gotten himself in so deep that he may need a hand getting out of his perdition.
And now look at Cas.
A story of unending devotion.
It tells a different story.
His expression never changed. It was always about Dean.