People treat Government Budgets as though they were household ones.

They are not like household budgets because you can't increase your household income with a stroke of a legislative pen and a household doesn't have a population that keeps growing forever.

The surplus isn't a big pile of cash somewhere in a Canberra vault, it's a balance sheet. A lot of it is IOUs from things like HECS debts that may never be repaid or company receipts that you only hope to get. A lot of it comes down to circumstance and foreign demand for whatever we produce.

A surplus also means that you effectively paid more tax than you needed to or were short-changed on services that you paid for but never received. It isn't cash stashed in some bank somewhere.

The government has to continually spend money to keep sectors of the economy going and that flows through to everybody eventually.
The money spent on schools stopped the building industry from going under while other sectors dropped off. The alternative would be to spend the same money (if not more) on dole payments to building workers plus their dependent industries and slide into recession.

Every time the same dollar changes hands, it incurs tax at various points along the line, not just once.