The mystery of music, as of speech, as of life, is uncertainty.
Take the opening of Beethoven's Fifth Symphony: I was utterly amazed when I found out how difficult it is to conduct its opening, the iconic four-note opening after a rest on a strong beat! How does one make the orchestra agree on when to come in after years of beginning symphonies on a strong downbeat?
Or the opening two tones of Fuer Elise: Do they rise. do they fall, or do they stay in one place?
The question mark is, in both cases, where the music comes alive.