@p WWII was the last time the US fought peer powers for reals.

If you're born in 1965 or later the end of that war is 33 years past by the time you hit puberty, and we just cucked on Vietnam over less than 70k fatalities.

Once the Cold War ends and with it the theoretical threat of nuclear holocaust things are pretty groovy, thus the 1990s being considered the last happy decade.