If the government pays your salary, then you do, actually, technically, get paid by everyone you meet. In your home country, anyway.

Tips are integral to service culture in places where people don't get paid a complete wage, as you do. Not so much in Australia, but definitely in the US. The problem here in the US is a propensity on the part of both businesses and staff to abuse the natural impulse to tip, in the hope that you will just reflexively hand money to everyone, regardless of whether they've actually done anything for you, or (in the case of room service) been tipped already via mandatory surcharges.