Disclaimer: I own all 20 currently translated manga volumes of Natsume’s Book of Friends. I have Nyanko-sensei merch. I’m just a teensy bit biased.
This is actually pretty unusual for a shoujo manga/anime, mostly because while there’s a lot of romance, it happens around rather than to our main character, Natsume, who is a dude (which is in itself rather unusual for shoujo).
The background for the story is that the titular Natsume is an orphan who has been bounced around from distant relative to distant relative because of his erratic behavior caused by yokai that no one else can see. He inherited the titular Book of Friends from his grandmother Reiko, who took the names of yokai she defeated as a contract to control them.
Natsume has been harassed and threatened by yokai all his life, but one day he meets a yokai who was sealed into a lucky cat statue, nicknamed Nyanko-sensei, who will protect him in exchange for the Book of Friends when Natsume dies. He also teaches Natsume how to return names from the Book.
The plot is pretty episodic, but there are plenty of recurring characters, both human and yokai, that make it harder to just jump into than, say, Mushi-shi. The translation from manga to anime was also handled very well, and the anime has lots of calming, slow-paced atmosphere, which makes for a happy nice time watching.
There are plenty of horror elements and bittersweet moments, but Natsume is a very kind show with a main character who is trying to become kind. But the themes also fit very well with the saying that the kindest people have suffered the most.
Natsume’s foil is Nyanko-sensei, who is easily bribed with human food and booze and is not a good role model at all. He has the personality of a drunk old man, and I just love his voice actor.
It’s a lovely palate-cleanser after particularly violent (or stupidly fanservicey) anime. I binged, like, five episodes after I saw the first episode of Attack on Titan.
But I don’t think this is a very good show for noobs, not with all the Japanese cultural references surrounding yokai and the Shinto religion. Also, if you have a hard time explaining Pokemon to grandma and her church lady friends, this isn’t going to go any better. Especially when this series has no dub, because as far as I know NIS hasn’t licensed it to anybody. All subtitles from the start. I haven’t found it anywhere other than Crunchyroll, which has a weird format of lumping the first three seasons together, but added four, five, and six each under their own banner.
And purely for the Nyanko-sensei: