I've been thinking about this and I wonder if, without any experience "inside" QF, or asking anyone.. but I wonder if one aspect of QF's service model is to encourage a "relaxed" and less formal experience for pax with the idea of "relaxed" being loosely interpreted by some? I also feel crews tend to take their cues from the CSM on any particular flight.
I find NZ tend to be more consistent with their "relaxed kiwi hospitality" style in that I usually know what to expect and it's service that is warm without being cloying or formally stuff and usually pretty prompt and efficient but also allowing for one to, for example, linger over a mug of tea or dessert.
QF I find, specially international, either way tto speed through service on say a supper flight (which makes some sense) or dawle along at whatever pace.