Just to chime in with Achilleas Vortselas’ answer: I’m not sure Brits know how big a deal it has been for Greeks to embrace a European identity. Or Germans or Spaniards or Poles, but it was a seismic shift for Greeks.
Because of that investment, Achilleas is spot on: continental Europeans will feel massively betrayed. Not just because of blocking the free movement of Europeans—but because, even now, they remain invested in a European identity, and they see Brits that aren’t.
I’ll add an unasked-for perspective: Australians’. Australia in its postwar stupor assumed it was still part of the Empire long after there was no Εmpire. Britain joining the EU was a massive shock to Australia, who until then assumed the UK would always trade with the Empire first. It was part of the requisite shock to get Australia untethered from its British identity.
Australians won’t remember the shock now. And politically and culturally, the Anglosphere is real—more real for its members (obviously) than the European Union is.
But economically, the “mother country” can get stuffed. The UK made its decision to turn to its own neighbourhood for trade; we have too. To the extent that we don’t want to be too vociferously allied to the US, for fear of upsetting China. And a Brexited Britain should not expect to swap its European partners with Commonwealth partners in commerce. That ship sailed long ago.
That too is an emotional argument.