I’ve been on more cruise ships than I can count, and I’ve danced my way through enough parties to last several lifetimes — but there is one song that never fails to transform a room. It doesn’t matter if you’re in a glittering ballroom at sea or a cramped pub on a Friday night. The moment those opening notes hit — “Where it began…” — people leap to their feet as if pulled by invisible strings. Arms go up, voices rise, and suddenly strangers are singing together like lifelong friends. Neil Diamond’s Sweet Caroline is pure magic. We all know…