Rachmaninoff sent fellow composer/pianist Medtner his Corelli Variations.  He wrote:

I played them here about fifteen times, but of these fifteen performances, only one was good.  The others were sloppy.  I can't play my own compositions!  And it's so boring! Not once have I played these all in continuity.  I was guided by the coughing of the audience.  Whenever the coughing increased, I would skip to the next variation.  When there was no coughing, I would play them in proper order.  In one concert, I don't remember where – some small town – the coughing was so violent that I played only 10 variations (out of 20).  My best record was set in New York, where I played 18 Variations.*  However, I hope that you will play all of them, and won't "cough."

* In Washington, Ruth Howell of the Daily News wrote: "There were, perhaps, too many variations.  The piece grew long, boring, and the theme thickened so that even Corelli couldn't have found it.  If the finale had been put in five minutes before, it would have been perfect.  When it was finished, even Rachmaninoff looked a little disgusted."

Cited in: Bertensson, Sergei & Leyda, Jay (2001) Sergei Rachmaninoff: A Lifetime in Music.  Bloomington: Indiana University Press, p.280-81.