My sister-in-law is in town visiting and she is an excellent violin player. Before she left her home, far, far away, I asked her to bring her instrument, so that I could play my cello with her.
Here's the deal:
Harmony, when done right, is AMAZING. It gives me goosebumps and makes me want to cry. There is something so breathtakingly beautiful about notes that are not the same, but perfectly complimentary.
When you have another person who can walks with you in harmony – not mimicking you, but adding to you … it is a beautiful thing, indeed. It is a dance. A duet.
And, both in music as well as in life, when you have accidentals (those are the sharps and flats that don't really belong in the key signature), if they resolve, it makes you sigh with relief; it creates a poignant beauty that is impossible to create if the notes all behave themselves and stay within the boundaries of the key. (When friends work out their differences, it makes the relationship stronger). If those places don't resolve, they leave you hanging. Dissatisfied. Angsty.
Musically and relationally.