The most common criticism revolves around corporate governance: Tracking stock subsidiaries seldom have a separate board of directors to look after shareholders' interests.
And that distinction between a common currency and shared economic governance, coupled with continued political sovereignty is now proving to be a Frankenstein that is putting the world economy into a state of suspended animation.
It always felt, when you covered a Brussels summit, that Britain was there on sufferance, but the rules said otherwise: technically we were and are an equal member of a 27-nation union whose oft-explained "three pillars" of governance were applied for the common good.