Juno is a lovely film, not least because its central, deeply cynical character, who spouts biting humor every few lines, is so believably played by a youthful heroine with a naturally understated naive exuberance. Ellen Page, who plays Juno, adds much to her character by effortlessly exuding the confidence of a know-it-all teenager, without a trace of pretentiousness. Despite flaunting a maturity that is clearly well beyond her years, Page's screen presence not only makes the character credible, but also romanticizes the late teens, arguably the worst years in anyone's growth.
The film takes stereotyped characters that seem perfectly believable and complexifies them as the film plays -- the pregnant teenager, the husband who wants to be a rock star, the wife who wants nothing more than to be a mother, and the boring parents of the teenager. In doing so, it shows that each of these characters is far more than the sum of their parts, making them much more convincingly real, and giving the audience more to grapple with as we get to know them.
Though I singled out Ellen Page's performance, the real genius in this film is the casting and acting because every single character in this film unfolded so credibly, and was played so spectacularly, that by the end of the film, there is a clear sense that life is both deeply complex and far more than anything any of us ever bargained for. All we can do is take a cue from our heroine -- laugh at where we are, act like we knew what we were doing all along, and figure out what to do next.