To be fair to Quebec, there are major linguistic, cultural and historical differences with the rest of Canada. /rant over :)

What about Catalonia? They seem to actually want independence more than the ones you list.

And it would probably be one of the best things that happened to them if they could manage to do it peacefully. They are a completely different culture, language, economic prospects, etc. Spain just wants to keep taxing them to support the rest of the country. But how is that ever a good reason for keeping an entire culture subject to historical imperialism?

rubbish. completely different culture and language? I lived in Barcelona and you could do everything in Spanish. The same can be said about various regions in Italy. Have you been to Sicily? Very different language, culture, food etc.

And by the polls ~50% of Catalonians don't want independence.

Of course you could do anything, it is a very touristic city and Spain forces Castilian spanish to be taught in schools.

Also, you can tell the polls are not that favorable or the central govmt would have made a referendum on the issue.