What does it mean to dream of an Angel playing piano?

I'm not exactly sure what your dream means without knowing more about you. But I can say this: I love it! The image of the angel at the piano is marvelously creative and playful. Since an angel comes from above, it feels like a spiritual image of inspiration. This inspiration doesn't just stay up in the air but it descends to earth to produce a work of music, a tangible expression of the angel's spiritual nature. Beautiful dream.