PS: English is not my mother tongue so I kind of understand the issue.
Yeah, I understand it also and since I have been working with it so much for so long with Finns, I can blur interpret the meaning (in Finland) easily enough. However, this can also be why some cultures appear much ruder or, more polite than others. It might not be them that is that way but the expectations of the audience on what good or bad behaviour is. As you said, these things take experimentation to understand, not school books.