diffident

To be "diffident" means to act hesitant due to having low self-confidence. In my experience, this can feel like a fight happening in your own head. In this piece, the marimba and vibraphone function as two halves of the brain. The marimba being the right half (more artistic and creative), and the vibraphone as the left half (more analytical and literal). diffident keeps the listener guessing with a barrage of key centers, modes, and styles held together by simple melody.