I saw an interesting stat recently that the poorest USA state, Mississippi, has a larger economy and GDP than 1/3rd of all EU members. It just seems like the EU is too top-heavy and I wonder if that's where a lot of the discontent comes from. It seems like there a lot of micro-nations in eastern Europe that have outsized influence over the union as a whole.
Gdp is not really a great measure of how well an economy works for it's inhabitants, if it was we should all spend our time breaking each others windows.