Warning: You should be emotionally prepared if you're going to watch this. In my case, I was emotionally tortured while watching this..It made me cry so much.
Anyway, story and plot is great. Some of it happens in real life, and we can relate to and learn from it. For example, how we lost someone and how we handle the pain, how to move on, how to start anew..things like that. Also the soundtrack is good. You can really feel the emotion of its characters.
So I recommend that you watch Clannad.
