Aspen 2010
I know that a Holy Day of Obligation (examples Christmas, Easter Sunday, pretty sure Thanksgiving) is a day that you have to go to Mass unless you absolutely cannot, but what is the difference because the Ten Commandments say to "keep the Lord's Day holy" and, I was taught, that every Sunday is the "Lord's Day". So what would be the difference between a holy day of obligation and every Sunday Mass, If you are obligated to go to both?
"Holy Day of Obligation"?
.... I doubt Jesus would recognize those days as valid.
As for each Sunday:
The day is made for the humans, the humans aren't made for the day.
(A quote from Jesus).
As far as i see it, there is no "must" to go to mass, but it may be a good idea for a christian to do so, unless something important is in the way.