Whatever a person is during the week, he is the same on Shabbat.
If a man behaves like a dog during the six days, he remains something of a dog on the seventh, except that he is now a Shabbat dog, which, like all else in that category, has something festive about it.
On the other hand, the toil and sorrow of the week may be unremitting until the Shabbat and, only then, having cast off the physical outer garments, can a person obtain the results of his inner efforts and enjoy the heavenly delight.
–Rabbi Adin Steinsaltz
From "Hidden Aspects of Shabbat" in The Candle of God by Rabbi Adin Steinsaltz