While there are many heinous sins in the world, some sins are symptomatic of others. A person doesn't start with murder. He usually works his way "up" to that one.
I'm just wondering if the lack of Sabbath is one of those "first" sins. After all, when there is no rest, one is tired more often (from which many sins come from), one never takes time to think about life, one does not invest in relationships (love your neighbor...), one does not dedicate time for sacred devotional practices....
It's just a thought, but I find that the lack of rest arises because I think I'm too important or capable that God really needs me to keep working. I forget that believing that God is sovereign and good requires some sort of tangible expression--that means rest, for one thing.
"Sabbath" is the first act of God to which we are then called to imitate (unless you count the procreation thing, but those don't have to oppose each other either). These are just thoughts. I'd love to hear yours.