I'm not Australian, or North American; but the content of this thread, brings to mind for me things which often occur to me when reading about certain aspects of US life. Unfortunately, I've never been in a position to visit the USA. Should I ever manage to do so -- I'd be apprehensive about ongoingly being driven slightly crazy by the "sales tax" business (I'm used to the amount displayed, being the amount that I'm required to pay !), and by the potential for mayhem in the realm of tipping.
Can "see with my head" that the conventions for tipping in US restaurants are considerably below rocket-science level as regards difficulty in understanding them; and that for the great majority of the time, things proceed smoothly on track and everyone is reasonably happy -- frankly, though, the whole US system re the remuneration of restaurant staff, strikes me as a dreadful one.