It can be reasonably argued that the most fragile points of a relationship occur at the beginning and the end. Of course, the end is obvious: whatever rifts and strains existed have reached the point of devastating rupture, and every misstep is like a body blow to the durability of the shared affection. The beginning is precarious too, as the two people carefully get to know one another, gradually discovering whether their idiosyncrasies–a preference for morbidly dark jokes, a youthful impetuousness–will prompt appreciation or agitation. Part of the sharp insight of Derek Cianfrance’s Blue Valentine is the intertwining of these two places in time. In depicting the courtship, marriage and miserable closing moments of a young couple named Dean and Cindy, Cianfrance alternates between two distinctly different stages that exist roughly six years apart. The obvious, simple way to flesh out his film would be to generate conflict by contrasting the blissful past with the dismal future, but Cianfrance doesn’t opt for that. As raw and tough as the film is in the scenes in which the marriage careens to its cold, hard end, the beginning isn’t portrayed as some candy-colored wonderland. As much charm as there is to scenes in which Dean pursues Cindy–especially the justly celebrated moment when he serenades her with his ukulele while she dances in a doorway–the film allows for a lot of complexity to the relationship, even at that point. Cianfrance famously had his actors lives together, a strategy that produced a remarkable connection with one another. They often interact with the sort of physical shorthand that is the hidden language of long-time couples. And those actors are both extraordinary. As Dean, Ryan Gosling has the edgy neediness of a kid who refused to grow up. Michelle Williams is even more extraordinary as Cindy, signaling her character’s changing frame of mind with every bit of her being, including deep wells of wounded hope in her eyes. Blue Valentine isn’t always fun to watch, exactly, but it does produce that thrill that only comes from truly great filmmaking.