That's a genuinely difficult question. Roman culture turned to degeneracy, but was otherwise impressive. Byzantine I genuinely don't know much about Russians were awesome, at first, but it devolved into such a shitshow that the Communists had a way in. Germans... Can't really find fault with how it was run, but they really sucked at diplomacy. Still feeling the aftermath of that. Napoleon... Not bad, but some tactical blunders cost him everything. Brits and spanish- I blame them for how awful things are now, they effectively drilled holes in their walls and let the rats in. Greece- sodomites. My favorite would have to be the crusader kingdoms.