It starts with a green light in the room. The feeling, or really, for any experienced moviegoer, the certainty that these two, Emma Stone and Ryan Gosling, are not going to be together much longer. After a near-painfully protracted meet-cute spanning a third of the film, and a giddy montage showing just how happy this aspiring actress and jazz pianist are together, we see Mia (Stone), come home to Sebastian (Gosling) playing the piano in an eerie, cold, green light, reminiscent of The Wizard of Oz.  He starts to play a longing tune, what has come to be one of “their” songs. She smiles, the green shades draining the color from her light purple dress, and starts to sing. The song is warm, but the light is cold, and we know—it’s about that time in the film for these two to separate, only to come together at the end. Or will they? That feeling, that loss will not only be threatened but truly occur, is the heart of La La Land. For how do we appreciate a memory unless it is in the past? ...