'A percussionist contracted to play in a symphony orchestra is paid a salary to perform repertoire that calls for a great deal of "not playing"... It typically involves counting rests with determined concentration... "Not playing" of this kind demands energy, and may be exhausting for a player, particularly during rehearsals.'

'You are wearing fully formal evening attire and for the last half-hour you have been sitting on a stage without playing a single note, or even moving your body except in the most inconspicuous manner. Suddenly, you alone must stand up among one hundred other seated musicians. You are holding two very large shiny objects, thus guaranteeing the focused attention of nearly everyone in the auditorium (including a conductor). At a precisely determined moment in time when most of the other musicians stop playing, you are to bring together the shiny, and, by the way, heavy objects so that their contact with one another produces a single soft and delicate shimmer of sound. After having done this, no matter how successfully, you must then return to your seat and wait an additional ten minutes for the conclusion of the piece. During this time you might reflect on the fact that the sound just made was the sole criterion for judgment of your musicianship by the conductor, your colleagues, the audience and, in fact, yourself. A performer who resigned his position as a percussionist with a major symphony orchestra once explained that, "Ninety percent of the time I was bored to death, and the other ten percent of the time I was scared to death."'

From here. Reminds me of the story Mr Oura told about him missing his only part in a long piece.. I'm horribly bored mugging!