I do no business on Sabbath, and it has been this way since the day I was born. Sabbath is a joyful, relaxing day. A refreshing day. I look forward it every week. Sabbath is a day to praise God, to fellowship, to press together with other brothers and sisters, to take nature walks, to sing, to enjoy a wonderful meal.
We do our best to get everything out of the way before Sabbath so we can bask in His rest. We bask in the blessing that comes with His Holy Sabbath.
It has a sanctifying influence on the soul that people are missing out when they refuse to keep it holy.
If God knew that even the Jews could not keep it Holy (since you say nobody can keep it holy), then was God so dumb to make the rule in the first place if He knew nobody could keep it?
That's a pretty dumb version of a God if you ask me.
The fact is, God looks at the heart, and He sees whether you are putting forth all your God-given effort, despite your shortcomings. Christ's blood is sufficient for those who strive, despite their fallings.
It is "willful" transgression that there is no more sacrifice for sins (Heb. 10:26). We live up to according to the knowledge we have received.
When we "willfully" say "since I can't keep the law perfectly anyway, I'm not going to even try", God right there sees that your heart is not where it ought to be. That your heart is in contempt against His Holy Precepts, and that deep inside, you really do not want to do what is right, and you are not converted.
But, if you truly love God with all your heart, a converted person will say "I'm going to do my best, and I know God can help me!" Despite your shortcomings, God will see your heart, and He will bless you and strengthen you by His Grace.
It is very simple. Follow Jesus. Obey Him. Strive to keep all 10 of His commandments faithfully, and He will help you if you really want it.
This is my earnest plea.