So I was just having lunch with a friend, right? And as I pay the bill and tell the nice waitress to keep the change, my friend tells me that tipping as a custom in Australia only came about due to the 'Americanisation' (or is that -zation now?) of our society. Apparently, we shouldn't have to tip here because the people who work in the service and hospitality industries here are all covered by laws that requires them to be paid minimum wage and tipping only originated because not all states in the US require employers to pay a minimum wage.

I am quite a generous tipper. So have I been unnecessarily nice this whole time? O_O

And also, what do you tip, generally speaking?
What are the variables that can affect the size of your tip? Quality, price, sexyness?