Add into this mix that the EU is obliged (via having that common currency) to bail-out those that share the currency. That costs real "dollars" to the populations of those nations like Germany.
The principle of the EU is very reasonable; but in practice, it is very risky (as we are seeing).
The EU has no such obligations, infact that goes against the pillars of the entire EMU.
Greece is the only country in the entire EMU who should have never been let in under the strict entry criteria. Their national debt was just too high. The austerity measures talked about in Greece had Athens in a state of mass rioting. That's what we get for sending them €110billion. I think upwards of 60% of Germans want Greece kicked out of the EMU.