For me, it's the 70s, even tho it's the decade when the axe fell for the global left, the eclectic fashions, the vibes, the simultaneous sense of cultural defiance, despair, emerging technologies and building dread of an unknowable future that we now know so well, gives it an almost otherworldly quality other decades lack
Also best decade for hair
i enjoy art nouveau, 1890s to just before ww1.