Could Canada Join the EU?

Short answer: No.
Long answer: it's technically impossible as Canada looks a lot like the US in many ways which goes against EU regulations. For instance, if Canada would join the EU, many cars won't be allowed on the road anymore due to EU road safety laws. Same shit with food production. It doesn't meet EU standards, which means most Canadian food production cannot be sold, so most farms would need to drastically change or go bankrupt. These are just 2 examples of many issues why Canada can't just join the EU. Best possible outcome would be Schengen economic zone membership. Canada needs to change so drastically before EU membership can even be considered, it is almost, if not completely, impossible.
Don't get me wrong, I'd love Canada to join us, I just don't see how.
- And for said reasons I don't want to join the EU. I'd way rather join similar to Iceland.
- I'm 100% sure all the old Soviet vans in Romania aren't up to current EU standards. Presumably things like that get grandfathered in.
  Food regulations are different, but not "drastically". I'm sure we could manage, although the farmers would act like farmers about it. Ditto for all the other regulations. It will take us a moment to move into compliance, though, so our politicians have their work cut out for them.
  So that's the EEA stuff out of the way. The Schengen zone for freedom of movement is actually bigger, because it makes problems at the US border, which is the longest border in the world and literally has buildings halfway across it. Still, if they keep acting like this, it can be overcome. The only thing left to do is to get Canadians other than me into watching Eurovision.

I asked this question during Trump's first presidency, and was met with scoffing and incredulity. Guess it's starting to look a bit more reasonable now.
- I started to hang around on r/Europe, even. If you knew the vibe and the system in America, knew history and didn't just disbelieve that it could apply to you, it wasn't hard to read ahead to this moment we're in now. Unfortunately, that combination was rare, so you and me got to be Cassandras.

That would be amazing. Even if they don't join the EU as an EU country, but simply be an ally, that would still make the world a better place!
- but simply be an ally, that would still make the world a better place!
  In what way? Neither Europe nor Canada are independently imperialist (they mostly just do whatever America tells them to do), but that's always one election away from changing.
  
  The European empires died decades ago, and the American thing was based on soft power and wasn't an empire.
  North Korea is a bad place, since we all know that's where this is going.

There are so many reason why this is unlikely to happen. That said, the US forming an alliance with Russia seemed unlikely. Yet, here we are.
- The so many reasons are?
  
  You’d have to get the entire union to agree. Including Hungary. Canada would have to change a bunch of stuff around when it comes to movement, currency, etc. The US would likely fight the move by putting its own NATO membership on the table. Assuming there haven’t been any Article 5 violations, then the EU would consider that a very bad deal. The list goes on.
  Now, Canada and the EU increasing trade and allowing freedom of movement is not entirely impossible. I think new alliances are inevitable. I just don’t see Canada in the EU as a likely scenario.
  
  For literally joining the EU: geography, Hungary and the optics of them leaving out places like Kosovo and Bosnia while we go ahead.
  For getting every part of EU membership except the technical status, there's much fewer. The only substantial thing I've heard is that they're afraid of Russia and there's a limit to how much we can help with that, while on the other side they're tempted to just avoid confrontation with the US, or maybe even (wrongly) think they can keep the alliance going.
  I don't know what OP was thinking of, though.