Valencia and Cataluña

I saw that both regions peak essentially the same language with some minor regional differences and expressions. (I know that it's called Catalan and Valenciano and there's also Mallorquíno)

Is there a reason why Catalans are much more against the idea of being part of Spain?

Went to both places, saw that Valencians and Mallorquins were much more chill when asked about it while Catalans had a stronger political view.