The other day a group of people wanting to learn to sight-sing in tune made their way through a very subtle melody by Thomas Campion (Elizabethan poet/composer). Every "error," every insecurity in their reading revealed a quintessentially poetic moment in the piece.
After going through it just twice it was already a deeply moving experience. Granted it was in the presence of someone who could put their tonal searchings in the context of musical reading. But isn't that the point of reading?