It's most Yasujiro Ozuish work anime has ever produced
Heaven forbid but I quote Amazon review in here because it describes the show perfectly:
When you watch the first episode or two, you might think that you are in store for a light-hearted comedy like Azumanga Daioh... all the usual cute anime kids are there. But this is not a comedy. It gets deeper and darker, and you'll probably find yourself crying by the end. Although the AnimeNfo description makes it sound like some kind of a Matrix-style science fiction mystery, it really isn't. There's no Shyamalan-esque twist at the end with some dime-store revelation. It is much more of a spiritual and emotional journey that artfully plays on timeless themes of salvation, meaning, purpose, love, loss, and trust. In many ways it is a metaphor for our own experience: We come into this world from some unknown place, and try to figure out why we're here. Along the way, we have to say goodbye to people we love, knowing not where they are going, but certain that soon enough we ourselves will be following them, and having never really understood what anything was all about. And yet, we somehow find a meaning in all the confusion and sadness. I think that's what this series is about. And it's both saddening and uplifting, because that's what life is like.
If it wasn't for Gurren Lagann it would've been by far best anime I've seen in years, now the order between these two is not settled yet.
It is masterpiece
R.E.M - Imitation of Life