It's a Kyoto Animation show that was a bit of a flop in Japan, with disappointing DVD/Blu-ray sales. It's a random, plotless schoolgirl comedy in which nothing matters and there isn't even much characterisation. Only two things set it apart from all the other "cute schoolgirls do nothing" shows:
1. Absurdity. One of the main characters (Nano) is a robot girl who's mortified by the idea of anyone realising she's a robot, so she's understandably distressed by the huge key in her back. (Sometimes it rotates.) Her bratty eight-year-old creator thinks it's cute. Other characters include a talking cat, a boy who rides his goat to school and a tsundere so violent that she'll fire rocket launchers at you. Reality is disposable in this show, so for instance people might get blown up or nuked only to be completely okay a moment later.
2. The animation. Admittedly the art style's so simple that birds are drawn as cones, but the show's basically "Animators Having A Laugh: The Anime". The whole joke in many deadpan absurdist scenes is simply the freedom and flamboyance with which it's been animated. They'll change the art style for laughs. They'll do Insane Nuclear Explosion scream effects for two schoolgirls having an argument in the classroom. When Yukko stabs her thumb with a pencil in one episode, her scream blasts through all the planets in the solar system. It's not all that extreme, obviously, but this really is a show where most of what's special about it was created by the animators. If you're the kind of person who's really just reading the script in your head when you watch something, you'll think there's nothing here.
Natsuki LOVES this show, by the way.
Did I like it? Well, I think I might have had false expectations. I'd read a glowing review, but the show's entire first half is basically lots of nothing. It's somewhat amusing, but it's not going anywhere and the cast aren't that great. The show then got a lot better at the halfway point. We get a character arc for Nano (the show's best character), but to my surprise this got resolved within a few episodes and the show returns to randomness... but a bit better than before. The second half is funnier than the first half. The cast's no longer locked into ghettos and there's even some storylike character-based interaction going on. Nano acquires a stalker, an incompetent mad scientist who keeps trying and failing to abduct her. Misato the Nuclear Tsundere makes modest progress in her relationship with Koujirou, although admittedly this mostly means shooting him with slightly smaller guns. (Her firepower is usually proportional to her embarrassment, but she very rarely uses anything that couldn't destroy a tank.)
If we divided this into two thirteen-episode seasons, I'd say Season A was okay and Season B was the one that was actually good. I still quite enjoyed Season A, but it's only laugh-out-loud funny occasionally.
It's impossible to give a plot summary of this show. There's very little plot and 95% of that involves Nano. Instead, I'll describe its cast.
THE MAIN THREE GIRLS: Yukko (cheerful idiot with extreme comedy reactions), Mio (blue hair, cute, draws filthy manga as her hobby, can overreact even more ludicrously than Yukko) and Mai (stoic who never reacts to anything, but plays pranks on Yukko). They're a laugh, but their characterisation is slightly unusual for this kind of show. They don't really have traits. They're defined more by the odd, trivial things they do than by their character summaries. You could almost say that their characterisation takes shape over the course of the show, as if the writers are discovering what they're like by spending time with them (and with us). That said, though, Mio is definitely cute, while it's interesting to note that Yukko the idiot is also the one who understands Nano and tells her what she needed to hear.
SHINONOME LABORATORIES: Nano (robot girl), the Professor (eight-year-old with the emotional maturity of a toddler) and Sakamoto-san (talking cat). Nano is the show's secret weapon. She's adorable. She never gets angry, but instead is endearingly aghast when the Professor installs some unwanted new feature, e.g. rocket punch hands, a toaster in her forehead, a detachable USB toe, etc. She just wants to be normal and you can reduce her to tears by pointing out that, for instance, she can't get cavities in her artificial teeth. She's deliriously happy halfway through the season when the Professor says she's allowed to go to school, although that's a surprise for the audience since everyone in the show has the same unreadable anime non-age and her maternal relationship with the Professor had been suggesting someone about thirty years old. (Technically, though, she's one year old.)
Meanwhile the Professor is a typical infant. She tells farcially transparent lies, she wants to eat snacks all day and she'll throw tantrums if you take her shopping and don't buy her chocolate. Well, "typical" apart from being able to build sentient robots.
OTHER CHARACTERS: a very random assortment.
It's pretty mental, but at the same time it's defiantly mundane. The absurdity is always growing from ordinary people living their ordinary lives. Hence the title. The show's also capable of building a showstopper nonsense set-piece out of some everyday, trivial scene that I'd guess was taken directly from real life observations, because it wouldn't occur to most people to write something like that. It's aggressively refusing to sexualise its cast or to pander to the panty-shot crowd, although that said the girls are cute in the two opening title sequences. It almost never tries to tell any kind of meaningful story with its cast, but its very occasional spasms of this with Nano could reasonably be argued to give the show a heart. (That's eps.13-16 and then ep.26.) It's endearing and unique. It's pointless, random fluff. I couldn't really disagree with any opinion about this show.