Today's vague #linguistic musing is how rudeness is a bi-directional process.
Take the "No worries" dichotomy, where people my age and #aussies generally speaking consider it a polite phatic expression.
Older people often consider it rude because you are (apparently) implying that there might have been a worry about helping them, and to them, said help was obligatory.
This conception of rudeness is super interesting because it doesn't matter how the speaker intended it. It's rude because the listener decided it was, which is in accordance with rudeness's definition of a fact threatening act... But not actually what the speaker intended?
In fact, people who say "no worries* point out that they do consider requests for help to be interruptions and thus potentially quite rude; they're assuring the requester that they did not rudely interrupt them.
So one party is genuinely being polite and helps the other party. The second party gets in high dudgeon about having their face threatened.