Pet Peeve:
The thing that really annoys me the most both here and the US is the "plus tax"  bit, although that is never written on the price tag you see, or at last that I see and not being used to adding a great whack of tax, I forget it every time. We have our  Goods and Services Tax in Oz, but it is added to the price before things are advertised, so what you see is what you pay, but unfortunately that seems to make too much sense, so here in Nth. America the tax is added at the register, and to tell the truth really gets up my nose. Then add to that in the US and to an extent here, not only do you have to consider "plus tax", but you also have to think of "plus tip", which can be another hefty 15% or so,  and that adds a lot to the "quoted prices".