I also think Humperdinck's Hänsel und Gretel is the greatest Wagner opera ever written. It's composed by a disciple of Wagner, who assisted on the premiere of Parsifal, it's brief, and never outstays its welcome, as many of Wagner's interminable operas are want to do, and I believe the premiere of the opera was conducted by Gustav Mahler, whose symphonies our BK has been listening to/.