Midnight in Paris revolves around this chance, the opportunity presented to a person to exercise free will in the only true sense of the term, to become something other than the self that they have crystallized (read: rigidified, or petrified) into. Gil has been captured, stratified, subjugated, and written over. His life has become so rigid, so habitual, predictable, and systematized that he is only really living in the technical (and organic) sense of the word.
The face does not exist, for it has no essence, only factors of the face exist, only forces at play exist. And, as such, one will notice that in any Chuck Close portrait the face is almost always blank or violent, because it has no one singular telos, no singular emotion to convey, but instead, millions, most of which probably clash quite violently.