Catalonia, Taiwan, Scotland, Crimea.

I don't know much about Catalonia. I've never been there and I know only a few people from there, all of whom oppose Catalan independence (and therefore are unlikely to be representative sample).

I have, however, lived in Taiwan, a de facto independent state where most people (including the premier) generally prefer the status quo. This position is pragmatic given the threat of war (and not a war which the Taiwanese would launch or could really be blamed for) if de jure independence were declared or even attempted, and given that at this point Taiwanese independence, absent international recognition that will never come, means little except changing the names and flags on government buildings. I personally find this pragmatism quite admirable.

In addition no British person can have avoided having experience over the past three years of the extreme political environments that referendums seem to give birth to, and how little seems to actually be decided by them regardless of their result. Simply voting for independence, either from a supra-national body like the EU, or from a country like Spain, achieves little by itself, and changes no-one's mind.

Three years on from the referendum on Scottish independence the SNP behave virtually as if it never happened, and the polls locked around the 55%-45% split against independence. More than a year on from the EU referendum the UK is still in the EU with no idea what will come next, nor any sign that opinion has moved on from the virtual 50/50 split on leaving or staying in.

The "joyous", "civic" atmosphere that the respective supporters of Scottish independence and Brexit thought they would create through their campaigns proved nothing more than a mirage, instead the reality was unpleasant and at times verged on fanatical. The simple fix to all problems people imagined might come from severing vital relationships and smashing up what has taken generations to build has proved a fantasy. 

I doubt whether Catalonia will prove any different in this regard. Indeed, even if the advocates of Catalan independence get what they want they will still have the problems that come from the illegality of the means they have chosen to achieve it. An independence referendum followed by a unilateral declaration of independence is nowhere near as bad as invasion followed by annexation, but the isolation of the Crimea following its sham referendum under Russian military occupation shows what happens when something which may have had popular support is achieved illegally.

Taiwan shows the virtues of leaving unanswerable question until later, of muddling through as best one can, even if this is often out of there being no other option. People both in Catalonia and in the UK could learn from this.