It's not everyday I get to encounter a movie whose principal photography took years to make. This is why Boyhood was fascinating. As the movie progressed, the movie stars aged as well... no plastic surgery; no bodily enhancements... they just grew old in front of my eyes!
The story wasn't so much about the journey of a boy through a major chunk of his life. I thought it was more about seeing the world change from his point of view. He grew up and the people around him changed as he did.
It was just refreshing that everything and everyone seemed to develop naturally... unlike in other shows where there's a sense of un-realism because the actors, despite years of being in the same role, have not aged at all. My favourite among the well-developed characters? Ethan Hawke's character growing from a bum dad to this successful role model.