One of the most insightful comments for me about eurogames on this site, that I still think about all the time, is Josh Look's observation that he generally only likes building euros where you not only build your engine/buildings/company/etc, but that you also get to operate it for a sufficient amount of time at its peak powers. I really do not enjoy euros that end before you operate all your plans sufficiently see the payoff, even you still won when you didn't operate it.