Are we talking "muh Texas" real or real?
To combine and elaborate on what everyone else has been saying:
In Canada secession is legal because the Quebecois want to be able to threaten to leave anytime they want something and it tends to stick the government over a barrel as they can't live with Quebec and they can't live without it. So Canada is held together by a network of what is effectively bribes, the largest of which benefit Quebec. Unfortunately, Canada's population demographics is upside down (fewer new kids than dying old people) in most provinces so they're steadily losing tax revenue even as they increase spending on various programs, mostly entitlements from what I know, but I've been wrong on this before.
So who does that leave to bribe Quebec to not quit Canada? Why the only regions with population growth, the Plains provinces. In particular, Alberta, which is the only province with a naturally growing population and has all that sweet, sweet oil to boot.
Now, using Alberta as a piggy bank would be unfair but workable if Ottowa was willing to throw them a bone or five, but they don't. Alberta has evil industries live oil drilling and is populated by feral, backward conservatives (Canadian conservatives, so right-center for us Americans) and can't be trusted to know what's good for them. So socially the Canadian elite verbally lambasts Alberta for doing the very things that they need Alberta to do to keep them liquid. Worse, anytime Alberta wants something they get the boot. British Columbia refuses to let them set up an oil pipe to the Pacific (cause evil oil) making transport hard and America is switching its oil infrastructure to a different setting, cutting Alberta out of the only other market they can access. (A market now sodden with American domestic production too). So Alberta is steadily losing money on their oil's value and is fending off increasingly inhibitive laws from the very people who are fleecing them to keep the Frenchies happy.
And secession is legal in Canada.
en.wikipedia.org
The secession party is the second-largest one in the Albertan government.
While its highly unlikely that they actually do go through with it, this stuff is only a joke until it isn't. Kind of like Brexit. Or Trump.
Bonus side note: An independent Alberta would be victim to a vindictive Canada's whims. An Alberta that defects to the US would have all of its geopolitical issues solved and be immune to retribution.