Good up until after the field trip arc, then it seriously declines in quality. I loved watamote before then, it was one of my favorite mangas, I loved the komi-san introduction arc, tomoko's inner monologues and how many of the characters played off each other (BEFORE the huge expansion of the cast post field trip) For a while it seemed like watamote was moving in a direction where tomoko would self improve and grow as a person, basically escaping her genre. Although tomoko does become more social while still remaining an introvert, that's not quite what happens. Basically she near spontaneously gains a clique that enables her pervy behavior and harassment (Remember, kids, sexually harass literally everyone and they'll still like you!) and the series devolves into disgusting Fanservice that makes me ashamed to associate myself with this series at all anymore. I don't hate Fanservice, it's ok when kept at a minimum, and Fanservice did happen before then, mind you, but it usually served the cringe comedy or tomoko's self growth and Fanservice that didn't fullfil either was more rare. Tomoko kind of went from being a jerkass woobie who is a horrible person but also broken and pitiable, to a regular horrible person that's not very pitiable or sympathetic at all. She becomes more social, but she doesn't grow up morally, and she's kind of enabled by the extra cast members that for some reason still want to hang out with her even despite her serial sexual harassment. Yoshida at least beats her up for it
Nowadays every chapter after chapter 100ish is purely mindless Fanservice without the series humor, and even in the (very very rare) chapter that isn't pure ecchi the chapter is just..boring. Tomoko and her inner monologue takes a major backseat and the series suffers for it. It seems like the writers just add new characters to the cast at the drop of a hat, without really doing too much with the already existing characters, this results in a cast that's way too big for what this series was supposed to be, that's mostly filled with one note characters with the exception of Tomoko, Tomoki, Yuri, Nemoto, and Yuu. Here, I'll break down the extra characters: UCCHI/EMOJI: Constantly thinks Tomoko is perving on her whether she is or not, secretly wants it but won't admit to herself because that'd be gay. She's the same joke repeated a thousand times. YOSHIDA: I liked her at first but she doesn't develop much past being a punk looking tsundere that likes cute things and basically exists for tomoko to accidentally perv on and get beaten up, she shows hints of deeper personality but we never really see it because she appears sparsely and the writer would rather introduce new characters than develop her. ASUKA KATOU: Traditionally feminine, beautiful girl that likes tomoko for some reason and seriously enables her sexual harassment. Acts kind of like a mother figure sometimes. No deeper character than that FUUKA: Character that, like Ucchi, exists soley to react to tomoko, which isn't necessarily a bad thing I guess. She reacts to Tomoko and Asuka's relationship and wonders if they're boning, that's it. She gets way more screen time than a character like that should probably get. KOMIYAMA: A favorite character of mine that played off Tomoko very well and had an interesting dynamic with her as your Frenemy/Sort of Friend. That is until she was massively flanderized into her most basic qualities: Wanting to fuck Tomoki, Being a secret pervert and liking baseball. That's it. Pre Flanderization Komiyama was actually my favorite character other than Tomoko. MINAMI: Alpha Bitch Wannabe that doesn't appear all that much HIKARI: Sattelite character for Komiyama. Reacts to her perviness and does little else. SHISUKU HIRASAWA: Naive Girl popular with boys. Views Tomoko as her wise senpai and takes Tomoko's advice uncritically. Very interesting concept for a character, she isn't done much justice though because, again, the cast is too big and doesn't handle the new characters all that well or give them more than one chapter in a row.