Leaving the auditorium of the Royal Opera House last week after The Sleeping Beauty, I passed a woman taking selfie after selfie in the mirror of the hall. She had snuck out during the curtain call to have the red banquettes to herself. When she should have been applauding Yasmine Naghdi and Francesca Hayward — goddesses, Olympians, immortals — this complete nincompoop was basking in her own glory.