My God, it's terrifying. And brilliant, and funny, but there were times when I found it hard to watch. I'd be curled up and cringing. Chio and her friends are human disaster areas, gleefully drawn to all things inadvisable and so guaranteed to bring about humiliation, embarrassment and failure. (Usually upon themselves.)
Chio is a schoolgirl who walks to school. That's the show's premise. Sounds simple, right? Most people could do this without, say, running across roofs, talking tough with a motorcycle gang, taking inappropriate advantage of a lesbian molester, trapping yourself in the wrong toilet, having a butt-poking duel (called "kanchou") and climbing all the way up the outside of a several-story building just by pressing your limbs against the brick. (Chio is athletic. Chio also doesn't back down from a challenge, no matter how daft.) Unfortunately, Chio's also a manic video gamer who's liable to stay up until 4am robbing banks and killing her victims. Thus, when it comes to school time, she's often both sleepy and full of ideas for inappropriate conduct.
Chio's got a few screws loose and is liable to get herself in massive trouble, but she's only a little bit greedy, absurd and self-centred. (She's also a massive nerd.) Importantly, she's likeable. She's fairly clever and sensible, to the point of often overthinking things. She's often aware that her bad ideas are bad ideas. It's just that that doesn't stop her from doing them anyway.
Her best friend Manana, though, makes Chio look like Mother Teresa. She and Chio are inseparable best friends... but they regularly treat each other like garbage and would cheerfully shove each other under a bus if anything went wrong. (Which is frequently. For some reason, they both think this prove how close they are.) Manana's perfectly capable of being normal and sensitive, but she's also fond of telling lies to encourage you to do something self-destructive and stupid. She thinks it's funny. She's a monster. What's more, if you really annoy her (as does the butt-poking kanchou brat), you might see Manana in her comedy demonic form. Pigtails flying, eyes blazing fire, serpent tongue, voice like Satan himself, etc. That made me laugh too.
It's another example of the flourishing anime sub-genre of Schoolgirls Being Human Garbage (see also Asobi Asobase). What's particularly funny is that Chio and Manana are also normal. They can be horrified and embarrassed just like anyone else, possibly at something they themselves just did. They can be awestruck by simple things that don't merit it, e.g. Manana's clever face plan in ep.4B. "It's perfect!" They can be perfectly ordinary, like anyone else. They'll chat. They'll walk down the street. Then they'll do something crazed, both in plans and execution (e.g. Chio in the men's toilet in ep.5A).
In fairness, though, I should point out that Chio's antics often have no amoral element. They'll still be mental, but not evil or wrong.
Can the show go too far? Hell, yeah. The schoolgirl lesbian molester can make any storyline uncomfortable. It's sort of amazing to see how fast and hard that character can push the comedy over normal boundaries of acceptability and taste.
This show made me laugh hard. Even good comedies don't always make you laugh aloud, but this one did it to me repeatedly. It's a jumble of innocence, naivete and wrong-headedness. (Mind you, Momo Shinozuka's stories push the comedy pain far enough that for me it almost stops being funny. I couldn't help empathising.) If I were to cite favourite episodes, I'd probably end up naming most of them. Ep.2B: the girls vs. romantic experience. Ep.3B: kabaddi (dodgy, but it made me laugh). The friendship dance in ep.5. (It's not just the silliness of it, but the alien thought processes that have decided it's proving the proposition under discussion.) Ep.10: Andou's little kanchou sister. Ep.11: the comedy bear snarls and "thank goodness I didn't get hurt".
How has Chio not died yet? Seriously. Watch ep.8, then answer that.
ON STUDENT-TEACHER ROMANCE: "Don't worry! The teacher will get all the blame, so chase him with all your might!"