I never knew an anime that could, despite its sci-fi setting, tell such a HUMAN story. It's a story about what it means to be human, about what it means to live, love, laugh, and cry. The creator put all their thought not into fights or fanservice, but real, raw, human emotion. This show ripped my heart out and put it back in so many times, I don't even know what to feel anymore. Even though I just watched it, I'm not jumping to conclusions. This is by far the best anime I have ever watched. Even if you don't like anime, even if you are just a human living on this planet, watch this show. You won't regret it.
Edit: I'm sure this will become a classic in the future...