It has taken 3,000 years to teach the Jews to keep the Sabbath with joy, as "Oneg Shabbat," delight of the Sabbath.
To tell the people to refrain from doing any work on the seventh day did not require too much urging or educating, but to make the Sabbath day a sacrament and a joy is far more difficult.
It takes ages because most of what has been learned over a long period of time can be destroyed in a single generation, and a new start has to be made.
That this is still true today is evidenced by the behavior of certain hooligans in the religious quarter of Jerusalem who throw stones at other people who also do not have any idea of what the Sabbath means.
–Rabbi Adin Steinsaltz
From "The Power to Accept" in In the Beginning by Rabbi Adin Steinsaltz