That's because music tells a story. Always. [Salieri steps closer to the board, mirroring the SQUIP'S position at the other end of said board] Whether it's instrumental, vocal, choral, or even a simple folk song--whatever it happens to be. And certain combinations in our Western music are taught to us from a young age to make us feel a certain way, whether that teaching is formal or informal.

For example, if you want something sad, a natural or melodic minor key is best. Hopeful? Major. Sinister? You use a harmonic minor. Triumphant? Trumpet blasts in the upper chords.

The question is, what emotion do you want to envoke?