Not exactly true, imo https://en.wikipedia.org/wiki/Swedish_War_of_Liberation https://en.wikipedia.org/wiki/National_Day_of_Sweden

Yeah, the Kalmar Union is the one debatable exception.

You can either view it as Sweden being ruled by Denmark, or a EU style union between equals, in which case 1523 is more of a Brexit situation.

There are decent arguments on both side. I lean towards the latter view.

Instituting a National Day in to remember it is more a modern way to try to keep up with the neighbors. All other countries have a national day, so we should get one too, even though we're not really sure what to do with it :)

Canada's Confederation day (July 1st, 1876) has nothing to do with Canadian independence (Which happened at the time that the Canada Act was signed by the British parliament - April 17, 1982.)

The UK doesn't have one either.

As long as pesky Nigel doesn't have his way.

Or Ethiopia