I am always struck at how Obama vacillates between a Mussoliniesque dictator with a hardened expression, to one where he looks like he's telling a story to a group of kindergartners.
I think it is the flip side of the same thing. His dictatorial appearance is a manifestation of his hard-core socialism (borderline communism), where he is intent on changing America into the socialist country where poor and rich are equal. He has to do this by looking and acting tough.
His at times perplexed, at other times softened expression is his narcissim trying to show a softer side so that people will "love" him as a kind and generous Robin Hood.
Either way, how can we trust someone with such vacillating expressions? We judge a man's character by his appearance and his actions. Usually the first determines the second.
Drudge, from the Drudge Report site, also seems to have similar ideas. In fact, I got this "Obama juxtaposition" from his site.
Here is yesterday's page showing Obama with his stern face and hard eyes, and here is a page from November 13 with Obama looking softer (kinder?) with General Petraeus beside him (here is a larger image).