Sighing and shrugging, irritably flipping pages of the score back and forth, he finally burst out (in German): “You can play the notes, I know that. It’s Mahler that’s missing!” The orchestra had arrived at the anguished climax toward the end of the movement, and the strings—by habit sweet and lustrous—were not playing with the harsh intensity that he wanted. “I’m aware that it’s only a rehearsal. But what are we rehearsing?” It was an implied threat to walk out.