If there is no Sabbath -- no regular and commanded not-working, not-talking -- we soon become totally absorbed in what we are doing and saying, and God's work is either forgotten or marginalized. When we work we are most god-like, which means that it is in our work that it is easiest to develop god-pretensions. Un-sabbathed, our work becomes the entire context in which we define our lives. We lose God-consciousness, God-awareness, sightings of resurrection. We lose the capacity to sing "This is my Father's world" and end up chirping little self-centered ditties about what we are doing and feeling.
Or, as in many a church, blasting self-centered anthems about what we're doing and feeling.
(Quote is from Peterson's Christ Plays in Ten Thousand Places)