Greece does not provide its citizens with more social services than other European countries, I would say that they actually provide less. And although you are right about the deficit, again, the main problem is the inflated public sector with all its associated problems, like high pensions at a young age.

The private sector should not be burdened with this, and actually, it cannot afford to pay for this burden. If collecting more taxes is the solution here, it's certain that Greece will go bankrupt.

Regarding Germany vs the other European countries, what is easy to see is the direct contribution of Germany to the EU but the indirect benefits that Germany got because of the fixed currency are more difficult to see although very very important for them.