Pathetique.

It is true that Beethoven's piano sonatas have a singular effect on the heart. The yearning and intensity embodied in the music can wrench any lovesick heart. In A Natural History of Love, Diane Ackerman describes the beauty of Beethoven: "No composer personified the passion of the age better than Beethoven, a tempestuous and defiant man who wrote avant-garde music full of majesty and organized alarm. Hampered by the rigors of traditional music, he fed his own anger, heartache, and struggle into his work. Expressing so much feeling would have been impossible in shopworn musical terms, so he invented a new vocabulary, one richer and more volatile, one closer to pure emotion... As the old rules crumbled, Beethoven's music became even more personal, alive with suffering and intensely human."

I have played my fair share of Beethoven. In high school I learned movements of both Pathetique and Moonlight. The first movement of Moonlight Sonata is one of the most satisfying pieces to play while wallowing in misery. I greatly enjoy closing my eyes while playing Moonlight and simply stewing in Beethoven's despair. In contrast, the first movement of the Pathetique personifies the anger and frustration brought on by passion. It is highly therapeutic to bang away on the piano in the form of the Pathetique.