The first book I read from my list was A Death in the Family. The author, James Agee, didn't get to finish writing it because he died. So, the editors were left with a pretty much completed story, and then these sections that didn't fit anywhere chronologically.
So they split them in half, put them in italics, and stuck them at the end of the first two sections. Why not just leave them out? Because they're beautiful.
My new favorite quote comes from one of these italicized sections. It's about parents.
"When I am astonished or bewildered, it is they who make the weak ground firm beneath my soul."
Edward Cullen is beautiful and shiny, but not that beautiful.