I don't know if it's just me or my current job but I've had the sense for a long time that you just don't say anything that you don't absolutely have to, either to coworkers or to clients. It's one thing to guard yourself against accidentally saying something that goes off the rails or shares something that the client shouldn't know (that makes obvious sense for its own CYA reasons), but there's a whole other layer to it - a bit like if you voluntarily share anything that isn't absolutely critical that's it's interpreted as obsequious, weak, cloying, etc..
It could vary by environment, I'm not even sure this is an 'NT vs AS' thing, I get the impression it's more general.
Also it's not that I'm actually falling into this trap constantly, it's just one of the heuristics I'm always having to run in my head before I fire off a text or email - ie. 'Will this make me appear 'weak' while also not actually solving any problems?'. My problem generally isn't fear, it's desire to be helpful but I constantly have to run my desire to be helpful (for its own sake) through this filter to avoid voluntary damage. While I don't have William's Syndrome I can only imagine what they go through in terms of environmental mismatch of will and intention. I can even have information that I think would be useful for other people to consider, but even thinking ahead, on it's own, is more of that scared, cloying, weak, defeated behavior.
I got to thinking - to even have to worry about this is just further evidence, in my mind, most people really don't grow up. If they did this kind of thing wouldn't even be on my radar.
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The loneliest part of life: it's not just that no one is on your cloud, few can even see your cloud.