That's interesting. A German friend of mine who's on the spectrum and had established a second life in Japan told me that Japan's explicitly defined social mores, and slightly more chilly and formal relations between people suit him much better than the Western default. His German buddies who also have one foot in Japan all seem like they're on the spectrum too, because of this I thought Japanese culture is a safe harbor for autistic folks.

Well, for one thing, we Americans claim to value honest communication to each other in our personal relationships. Whether we actually live up to those values is a different matter, but my point here is the Japanese do NOT. Honne/tatemae is pretty ingrained into Japanese society, and you must avoid embarrassing yourself and, more importantly, your ingroup (family, company, club, etc.) by being too honest around outgroupers. The Japanese are so pressured to not lose face that they are actively encouraged to hide their feelings and intentions, even when showing them would be mutually beneficial. You see it in business -- the old saw about circumlocutions like "We will give your proposal the consideration it deserves" meaning "no freaking way"[0] -- but you also see it in modern Japanese drama. Taro loves Hanako and Hanako loves Taro, but they are from different social strata and their parents would be shocked to find out they're in love, so neither of them says anything and neither of them knows the feelings of the other. Plus Taro is going to America to play baseball and Hanako is going to medical school. Will one of them work up the courage to go against the social grain and the wishes of their family, and confess their feelings before it's too late? Or will they just say shouganai and go about their lives without ever knowing what could have been? That sort of thing.

So as a Japanese person you are tasked with not only following the rituals, but also sussing out from the vaguest of cues what your friends, family, potential mate, etc. are thinking because they're following the rituals too instead of engaging in explicit communication.

Regrettably, I had to learn a lot of this by reading; I don't have a lot of personal experience with this because I'm a Westerner. The Japanese are generally more willing to be open with foreigners because of the relative lack of social repercussions for honesty with foreigners than with Japanese. They don't have to be "on", they don't have to actively be Japanese in front of us and that makes for some interesting and refreshing barside conversation, lol.

[0] Earlier negative stereotypes of Japanese as being "sneaky" and untrustworthy are partially rooted in this sort of thing. They mask their true intentions to avoid embarrassment, but to Americans it looks like they're trying to trick or defraud us. And they see us as loud, pushy bulls in china shops who are unable to handle delicate affairs with any nuance, even if we're well-meaning.