Since Rachmaninoff played mostly the romantics he was not too good in the classics. Once at one of his rare performances of Beethoven's first concerto, he turned to the orchestra and said, "Alright gentlemen, since i am no Beethoven expert, lets play this in tempo!"
he never found any meaning in that life, only chaos, he actually hated it and everything that came with it (including money), which could explain the Gerschwin incident.