I'm not really sure why this show is so good, as it has a very basic concept and in theory sounds kind of boring. But make no mistake, this is a beautiful, laugh-out-loud anime. Non Non Biyori is the kind of anime that you watch after a bad day and it instantly calms you down. There's zero drama, romance (unless you count Haruno's crush on Koma-chan) or violence, and the plot relies almost completely on character interactions.
I thought that Non Non Biyori's almost complete lack of a plot would be a huge turn off for me. However, the story flows beautifully and works very well in the seting. The only negative is that the pacing is very slow, and while that usually works well, it can at times feel stilted.
The animation is absolutely gorgeous. The character designs are very unique and each character is rendered beautifully. The backrounds are also stunning. As it's set in the Japanese countryside, there's a lot of beautiful nature and animals.
The music always fits the tone of the story and is very pretty. Renge's tune with the recorder is absolutely delightful and is still stuck in my head. The voice cast is also very talented, and each actor really embodies the personality of their character.
As the show doesn't have much of an overarching plot, the characters are the most important part of this anime. And they're wonderful. I love every single main character, from the mature Haruna, to Komari who wishes she was more mature, to the carefree Natsumi, and especially the adorable Renge! Seriously, Renge is the best character ever; if all the other characters sucked (which they don't) I would still give them a 10/10 because Renge is so awesome.
This is a beautifull anime that's very calm and relaxing. If you're into action and drama and romance, then this anime probably isn't for you. That being said, I love action and adventure anime, so you really don't have any excuse. Anyways, watch this, you won't be sorry.