Paul’s post makes a number of good points, but slips up seriously on one.
For a long time I’ve thought that it would make more sense to describe “the Sixties” as the period between November 22, 1963 and August 8, 1974, rather than the literal decade
There were two “Sixties.” The first lasted from sometime in the late fifties, say 1959, through the passage of the Civil Rights Act in 1964. That was the good Sixties. The later Sixties, the bad Sixties, was from 1964 through the end of the Vietnam War in 1975.
I was there. End of discussion.