Answer :
The passage that is written for expert pianists is I always knew I should be practicing scales and arpeggios to enhance my fingering skills, but I always preferred to spend my time on a little Rhapsody in Blue--extra fortissimo!
All pianists are expected to practice scales and arpeggios. This is what allows a pianist to become familiar with the piano keys which is crucial for a pianist. So in this passage, it is clear that he wanted to play Rhapsody in Blue instead of practicing scales and arpeggios.