Nureyev

That is what keeps him [Nureyev] ahead of the field. That, and the intensity of every performance. Remarking once that "it's quite difficult to dance, you know," he went on to elaborate that in a vivid metaphor: "It needs commitment and passion; every time you dance it must be sprayed with your blood. So much effort for so little reward--not from the public and critics, I mean, or the box office, but from yourself."

Nureyev. Aspects of the Dancer by John Percival. 1976. Page 123.