'i let you down' by Dave Matthews Band, from the album Crash - a mellow song, which in my mental map, clusters around the Jack Johnson style of simple quiet rainy-evening music. I love the ending of this song especially. There has been a simple refrain of "I m a puppy for your love, forgive me" throughout the song, and at the end, there is a very natural whistling at just the moment one would want to whistle it out, interspersed with a plaintive violin and then a slightly jauntier sax. Such a pleasant close to the tune, perfect really.