‘Tutto nel mondo e burla’ sings the company at the end of Verdi’s Falstaff — ‘All the world’s a joke’ — and how much you enjoy this opera probably depends upon how far you accept that truth. The 79-year-old Verdi coming out of retirement for one last laugh, finding in Arrigo Boito a librettist who could remake Shakespeare in the sun-kissed Italian of Boccaccio and Petrarch, and then composing a score that saves its deepest compassion for old fools and young lovers, its sweetness (according to Boito) ‘sprinkled across the comedy as one sprinkles sugar on a tart’: seriously, what...