Any year in the late 50s.
Optimism reigned.
.
That’s my call. Or early 80s when Ronnie made people proud to be American again after Carter.
Charlie Daniels summed it up pretty well when RR was on the horizon...
https://www.youtube.com/watch?v=YSxSc3ylAkg
Yup.....late 1950s was the high-point of American culture. Polio was cured. Space race started. Low crime. High education. Beautiful mix of good civic & private culture.