I don’t have anything particularly helpful to say since much of what you mentioned feels quite mysterious to me as well (e.g. the thing about ‘compliments => pressure to give someone a present that’s similar’ sounds ridiculously unfair and very much overanalysed – and I overthink a lot, so I should know). I believe what you’re telling me; I’m just saying that I don’t have any answers myself.
Some of this stuff does remind me of Ancient Chinese etiquette from period dramas though. (E.g. if nobles visit each other and one of them compliments a particular possession of the other, it’s very common for that to be followed by gift-giving… but I always thought that only applied because 1. the giver was rich enough to afford it OR 2. the giver needed the recipient’s political favour/valued his or her relationship with the receiver. Also, I vaguely remember vassals who made huge but unsuccessful efforts to do things for their superiors being forgiven and praised for their loyalty, even if those who actually got things done were usually better liked.) I sincerely didn’t expect such etiquette to still be present today, especially among ‘ordinary people’ (i.e. people who don’t have massive fortunes), even if a lot of my own tendencies to ‘avoid stepping on people’s toes’ are probably inspired by traditional Chinese etiquette. (Obviously, I’m not saying Japanese etiquette is exactly the same, but I couldn’t help but notice.)
A random recent example
My Japanese teacher told me I could have simply said 良い週末をお過ごしください in a message to her, but since I think it’s not nice to tell anyone to do something, especially when it’s actually beyond their control – nothing guarantees your weekend will be good, after all – I went with the very roundabout 〜を過ごしますように祈ってます. Generally, the greater the difference in status between me and someone else, the less qualified I feel to phrase anything as an instruction or direct request, but my Japanese teacher didn’t see it as a problem. That’s also the day I decided Japanese people might not be as formal as I thought they were.
There is one thing I wanted to comment on though:
I don’t know if I’m in any way close to being right, but as frustrating as all those events sounded, I felt like the positive things your acquaintances did do for you fall quite clearly into the ‘social nicety’ category. In other words, perhaps at least for now, they’re not comfortable with anything that might lead to a deeper conversation, but still acknowledge that you have some sort of relationship and know each other. Maybe the reason is indeed ‘not being used to talking to a foreigner’ – I wouldn’t know – but at least they acknowledge that they know you, for what it’s worth. No point thinking too much about it, I agree, but I thought it might be helpful to get a feel for the depth of the relationship. (This is how I think about relationships, at any rate, and I prefer to know where I am in terms of social distance relative to someone so I know how I should treat them. I only invest in people I’m close to or am getting closer to, and if I know someone hasn’t warmed up to me yet, at least I know I don’t have to bother too much with them as long as I don’t make them uncomfortable.)
PS: While I realise that quoted extracts make a clear ‘replying to’ field somewhat unnecessary, I’m still not used to the fact that my posts no longer seem to be directed at someone by default even when I’ve chosen an intended/main recipient.