It's my one relieble "go to" song although I seldom seek it out...it just brings me peace whenever I hear it, like a cool breeze: Clair de Lune by Claude Debussy. I think it is the intricaties of the piece, a certain frailty/delicacy and then the rolling, sweeping sequences emerging and receding. I feel the moods of the skies when I hear it, and this makes me feel connected to something timeless, grand, and without judgement. It just "is."