Where do you draw the line so that not every wealthy region or city unhappy with its net tax payer status secedes from poorer parts of the country? You say tha

Where do you draw the line so that not every wealthy region or city unhappy with its net tax payer status secedes from poorer parts of the country? You say that the Catalonian people feel oppressed. By what standard is that actually the case though? As far as I know, Catalonia enjoys very far reaching autonomy within Spain.