There was never a successful attempt to create a European sense of identity and a European sense of citizenship that would define the obligations, responsibilities, duties and rights that Europeans have to one another beyond simply the wording of the different treaties that were signed. The EU in many respects was created as a technocratic exercise done for purposes of economic efficiency. What we can see now is that economic and post-national values are not enough to get people to buy into this community. So wealthy Germans feel a sense of noblesse oblige towards poorer Germans; this social solidarity is the basis of the German welfare state. But they do not feel similar obligations towards the Greeks, whom they regard as being poor disciplined, very non-German in their general approach to fiscal matters.
Earlier thoughts along these lines here.