I am so glad that these two moments have been giffed together like this because, to me, wow is this something subtly telling. Both instances, Dean stands before a mirror, the image reflected back at him as blurred as the current clarity of his self-concept. But it’s the small difference in gesture that speaks volumes. Because in the first instance, Dean swipes his hand (his right hand, his mark-of-Cain hand) from left to right, but in the second, from right to left. Why is this telling? Crossroadscastiel and pirrofarfalla have discussed the significance within palmistry in left- and right-handedness, with the left side said to be a reflection of the inner self. The imagery of the scene where the first gif is taken is strongly suggestive of Dean trying to cleanse himself of the taint he feels himself becoming corrupted by; he is trying to wash away his corrosive thoughts, to shed himself of the mental burden of the mark. And in this gesture, sweeping from the side of the inner self, he tries to focus on that side of himself, to block out the mark side of him and try to ‘switch on’ the person he used to be.
In the second gif, the context of the scene places Dean almost preparing himself for what he sees should be done, needs to be done. Again, the mirror is murky, reflecting the lack of clarity of Dean’s self-concept, both to him and to us, the viewers (which Dean is going to be the driving force here? His inner self, or the tool the mark is creating?). And here, he sweeps from right to left, this time ‘switching off’ the inner self and so allowing the corrupted self to take the reins. A sign that, as Jensen himself stated in interviews, that Dean is starting to embrace the tool, the weapon, he is becoming.
Larinah has spoken of the theme of Jekyll & Hyde this season for Dean (and I have spoken of Dean being conceptualised as a werewolf also) and these two moments absolutely emphasised that theme of duality to me (dustydreamsanddirtyscars has also highlighted various pointers to this theme of duality). Dean is a creature of two halves, one of light, of Jekyll and humanity, and one of darkness, the Hyde, the wolf. And just as in those classic stories where internal conflict exists within the tortured being, so does there exist such conflict within Dean. Which side of him will win? Notice which hand Dean uses in both gifs: he uses the right hand, the mark-of-Cain hand. This could just be because of Dean being right-handed… but could it also reflect which aspect of himself is the stronger, the one that has dominance over the other? The one that will over-power and consume until the half it currently is becomes the whole?