In "The Last Leaf," O. Henry told a story of a woman in a New York city apartment who has pneumonia. She is convinced that she will die. From her window she can see a vine of ivy and she says that when the last leaf falls from the ivy she will die. But the leaf does not fall off -- and she lives. After her recovery she learns that her artist neighbor has painted a leaf on the wall facing her window. It is true that pessimism can shorten life and optimism can lengthen life but eventually we all must die. Only God knows when. Every Christian knows why.