It's an old-fashioned shoujo romance, down to the art style. (It's perfectly watchable and much more modern-looking than, say, the 2001 Fruits Basket, but its heroine is sometimes two eyeballs with a human being attached.)
It's also pretty good. There's a live-action movie adaptation of the same manga and I'll be watching that tomorrow. A timid misfit (Mei) manages to catch the hottest boy in school (Yamato) by being the only girl who's not leaving a snail trail of drool whenever she sees him. Instead, she kicks him down the stairs and thus unintentionally turns him on. (That's only my theory, admittedly, but it fits the evidence. Yamato is friendly but uninterested when girls are practically draping themselves over him and is rude to the point of comedy when the super-hot Megumi directly asks him out in ep.6, but his eyes light up on encountering an emotionally stunted introvert who's not even interested in having friends, let alone boyfriends.)
It's a charming story. It's not always a completely comfortable watch, mind you, because its characters can all be idiots. I like its message, though, and its couple work well together.
When the show opens, Mei's basically rejected the human race. Instead, she likes animals. She had some bad experiences with so-called friends and these days doesn't even speak to her classmates. (She also has the surprising ability to consume large quantities of food and yet stay as thin as a rake, despite also being extremely short.) Her relationship with Yamato isn't just about romance, but about her learning to unbend, forgive and trust a bit. She's bad at conversation and even worse at saying certain important things (c.f. the show's title), but at least she's aware of this and will want to fix it.
She also rediscovers the concept of having friends to talk to. The end of ep.7 is lovely and all-important, even though the Mei-Yamato relationship is a bit of a train wreck at that point, because Mei actually talks through her problems with her friends, realises things as a result and gets good advice. She couldn't have achieved that in ep.1. Literally incapable of it. Her brain would have melted if she'd tried.
She's clever, though. Look at what she's realised about Aiko in ep.4.
Yamato, on the other hand, is the kind of tall, handsome girl magnet who effortlessly gets along with everyone. He's great at reading the mood and fitting in... but this can have a downside. In junior high school, his best friend was being bullied and Yamato never defended him in public. In private, when no one was looking, sure. He's the opposite of Mei, who couldn't care less what anyone thinks and whose word choices can be abrupt to the point of rudeness. (Just as Mei grows as a result of her relationship with Yamato, incidentally, it could also be argued that he learns from her. He certainly gets more clear-minded about his priorities and about where to draw certain lines, albeit partly through making mistakes.)
Similar themes are explored with a lot of the cast. There are pseudo-friends who don't care underneath and will drop you the moment you're not giving them what they want. It's possible for these people to be so good at seeming nice that even the audience are fooled for several episodes. There are former victims of bullying. There's a death and rebirth, more or less. (No one actually dies, but we'd been looking at social and professional suicide.) There's a little sister who couldn't be in greater need of talking to Mei.
It's also funny. Yamato's sister made me laugh a fair bit. Mei and Yamato could make me laugh just by being themselves, because they find a way to have comfortable conversations even when Mei's practically mute.
Incidentally, I recognised the theme song's singer. It's Ritsuko Okazaki, who also did the theme song for the 2001 Fruits Basket, which is surprising in a 2012 anime since she was diagnosed with cancer in 2003 and died in 2004, aged only 44. (Both songs have a minimalist style that's focused on their almost unadorned lyrics.)
Is this show perfect? No. Ep.13 is a throwaway with contrived plotting and people being even bigger idiots than usual. (The season really ended with ep.12.) Also, the heartwarming Megu-Momo moment in ep.12 would have worked better had Momo and the relationship been better established in earlier episodes. We're going "who?" Basically, though, I liked this show a good deal. It's sharp and has things to say. It's a traditional kind of shoujo romance, but it's also a strong example of the genre. It portrays Mei's social anxiety excellently and she's always very relatable, even when what she says and does is a long, long way from ordinary people. Her character growth is interesting, too, since she stays completely herself throughout and never starts trying to fit in with the crowd. Her skirt stays long. She'll bluntly say "no" to things she's not interested in. She doesn't get a magical "cure", in other words.
This isn't the best or the funniest shoujo romance out there. I'm pretty sure Kimi ni Todoke will stay in my memory longer, for instance. It is, though, definitely worth a look.