Listen to this. It will go right down inside you, find any feathers that might be ruffled, and smooth them to a glossy, tranquil sheen. Depending on how much coffee you've had and what day of the week etc, it may also make you a little bit emotional as you gaze out the window and consider the fragile beauty that is life blah blah. [youtube=http://www.youtube.com/watch?v=rKZr3ExeXUc&w=700]
The famous Andante from Mozart's Piano Concerto No. 21 is in three parts. The opening section is for orchestra only and features muted strings. The first violins play with a dreamlike melody over an accompaniment consisting of second violins and violas playing repeated-note triplets and the cellos and bass playing pizzicato arpeggios. All of the major melodic material of the movement is contained in this orchestral introduction, in either F major or F minor.
The second section introduces the solo piano and starts off in F major. It is not a literal repeat, though, as after the first few phrases, new material is interjected which ventures off into different keys. When familiar material returns, the music is now in the dominant keys of C minor and C major. More new material in distant keys is added, which transitions to the third section of the movement.
The third section begins with the dreamlike melody again, but this time in A-flat major. Over the course of this final section, the music makes it way back to the tonic keys of F minor and then F major and a short coda concludes the movement.
The second movement was featured in the 1967 Swedish film Elvira Madigan. The imagery used in the movie was of a lazy boat ride on a placid lake, and the limpid sound of this movement likely motivated its choice here.
If you can read sheet music, this might be where you want to go. (I didn't know all that stuff about the music, by the way, it came from Wikipedia)