The more I teach, the more I play, the more I listen, the deeper my conviction that music unfolds one tone at a time and that if we are engaged in the first sound, whatever it is, we will follow wherever it leads.
When a piano piece is announced as in a certain key almost everyone who has ever played the piano will have an immediate reaction, whether conscious or not. For example, yesterday I asked a young student (16) which white key was most problematic on the piano. I was surprised at her reply: C.
C is for her uneventful, which causes her problems. I recall having the same reaction when I was her age. (One adult student has labeled that key "ploddy.")
The question, then, is why so much has been written in that key by Haydn, Mozart, Beethoven, Brahms, not so much Schubert and even less Chopin.
Partly for this reason it is not always appropriate to indicate what key a piece is in: the Chopin Mazurkas and many cycles of Brahms Intermezzi, for example, float in and out of keys in thrilling sequence quite outside the logic of traditional theory.
We listeners should have the option of floating. Maybe that is what the key of C invites and what we find so difficult.