As an additional note,
National Holidays are a deliberate attempt by governments and nations to usurp and negate “Holy Days/Feast Days” As monarchies sought to separate themselves from
the controlling influence of the church, they attempted to downplay the everyday impact of religion and replace dedication to religion with fealty to the crown, and later nationalism.
This, obviously, was a delicate balancing act. To maintain a semblance of piousness while reducing the control of a non national church.
Early Christianity manipulated it’s calendar of High Holy Days to coincide with traditional pagan feasts partly out of convenience,
but largely in an attempt to prevent erstwhile converts from following their pagan faith in secret.
Still, a need was felt to somewhat imitate the preexisting pattern, because human nature resists abrupt change.
Asserting secular control wasn’t simple.
Especially considering that, contrary to popular depictions, medieval peasantry weren’t worked into the ground, partially due to nature itself, but also, in large part, due to the church.
The average peasant had 80 complete days of rest in observance of holy days, and over 70 partial holidays (‘Medieval Work & Leisure’, Hugh O'Reilly).
So to simply erase all that, well, that’s pretty much revolution material there. Of course that’s also somewhat detrimental to productivity once you introduce the concept of wages.
Monarchies were notoriously classist and not good with equal distribution of wealth (Which is why they are no longer the preeminent form of governance),
so shifting allegiance from church to king and country, while driving the lower class to work harder required a bone or two be tossed to the unwashed masses.
National Holidays are the win-win for the rulers. Time off for the hoi polloi with the country as the focus and benevolent provider.
Hmm. Maybe that’s why so many involve drinking. You don’t show up for Jesus’s shindig all shitfaced, but the king/president/prime minister? Screw ‘em. Let’s drink!