Truffaut is indisputably the best director who can portray a love triangle, as well as one of the best who can compress a lengthy memoir into a 2-hr film. The whole viewing experience is like an Odyssey--you spend 2 hours to experience a span of nearly 20 years, and in the end, you look back, feeling nostalgic yet in a calm way. All the characters gradually change (or to say, are revealed their true selves) over time, leading their relations to change as well, yet all rushing towards the tragic ending with a faint hope of ever fixing this intertwined relationship.
Jean-Pierre Léaud was 27 when he played Claude, when his rebellious traits gradually turned to brooding and perplexed. After watching so many collaborations between Truffart and Léaud, [Boyhood] does not seem so heavy any more, even though it is still stunning.