Here, try something: Take a minute to think about one of your best friends. How did you get to be close? I don’t just mean how you met – at a party, taking Freshman Comp together, serving on the same top-secret CIA mission to Burma – I mean how you got to be friends. If you’re like most people, the chances are good that your friendship blossomed by sharing not real things, but imaginary ones. Relationships, research in anthropology and ritual studies suggests, flower best when people take part in shared, alternate worlds of imagination – subjunctive worlds that are cordoned off from reality, where our minds can play.