I'm not sure the usual analogy between household and nation's spending is useful. Countries work in fundamentally different ways from people.
I would argue that if you are aware that a person is not a nation and vice versa, that there are some traps on the way, this analogy is useful indeed.
It seems that basic things like "you need to pay back money we lent you" are still the same? Sure details are different, well, I don't know how different, that is why I am asking ...
Countries (even countries in economically integrated Europe) are closed systems. Increasing the revenue to one sector results in losses to another. In this case, the Greek government can increase its revenue by increasing enforcement and raising the tax rate. However, that results in a cost to the private sector. People paying more in taxes have less to spend on other things, which lower economic activity and lengthens the recession.
As an aside, this is why I get very irritated when politicians use household/business analogies to model national economies. The two are different in kind, not just in size, and trying to compare an open system to a closed system leads to serious errors of judgement.