One of the things that absolutely sh**s me off is when you discuss and agree on the price, the salesperson will at the very last minute, just as you're about to hit the PIN for your NETS transaction, drop you a "still need to add GST".
Like what the fish, man? Why quote me a price without GST when EVERYONE *must* pay GST anyway? It's plain misleading. In some countries, it is a law that all prices quoted must be inclusive of GST.