The most predictable part of the fracture in the alliance was that of all of the countries that have grumbled about leaving the E.U. since its formation, it was the Brits who jumped first. There is nothing that makes individuals or groups less likely to immerse their identities into that of a larger group than the belief that they were bigger and better on their own.

Greece and Italy were once home to the world’s dominant cultures, but their period of primacy was millennia ago. The era when the sun never set on the British empire, by contrast, occurred in the lifetimes of some living—if aged—Britons. For the rest, that golden time was less ancient history than oral history, a period described to them in the first person by their parents and grandparents. That made the idea of being just one of 28 especially hard to swallow.

“Britain once ruled the waves and has been diminished for a long time,” says psychologist Frank Farley of Temple University, who studies risk-taking, history and political psychology. “It remains a power in Europe for sure, but it’s diminished to the island geography. We shouldn’t be surprised that at a deep level, Britons chafed at just being one cog in the wheel as opposed to the wheel.”