The above stories of O. Henry share these similarities:
- The setting is New York City at the turn of the twentieth century, where O. Henry himself moved in 1902. Because this is where O. Henry settled, he employs local color and melodrama. In "The Last Leaf," for instance, Johnsy and Sue have moved to Greenwich Village in order to be artists and they encounter new experiences with the winter weather and Johnsy's sudden illness. Their neighbor is an odd little Jewish man named Mr. Behrman, who poses for Sue and loves the girls like daughters. Likewise, in "The Gift of the Magi," the characters of Jim and Della are rather poor, but they love each other deeply and are willlingly to make serious sacrifices. In "The Witches' Loaves," Miss Martha Meacham searches for love and suffers from loneliness. Rudolf Steiner finds love as he discovers the wrong green door, as does Jimmy in "A Retrieved Reformation" when he reforms for love.
- Each of the stories
gravitates toward the maximal unexpectedness of a finale, concentrating around itself all that has preceded it.
- This "finale" is often called the surprise ending; for, it is an ending that the reader does not expect. For instance, in "The Gift of the Magi," Jim and Della sacrifice their most valued possessions, only to receive gifts connected to them. In "A Retrieved Reformation," Jimmy the safe cracker leaves his life of crime, but must break into a safe to save a child; ironically, as he leaves the bank, the detective who has been seeking the former criminal, lets him go free. And, Miss Martha Meacham of "The Witches' Loaves" is sadly disappointed to learn that the young man who buys the stale bread is simply using it to erase his pencil lines.
- The stories all contain O. Henry's light-hearted, somewhat romantic humor that is tinges with sentiment. In "The Green Door," for example, Rudolf Steiner mistakes the card handed him about a play entitled The Green Door for the green door that leads him to the discovery of a starving young woman with whom he falls in love.
- The narratives have the "oral voice of the raconteur" that has been derived from humorists of the frontier such as Bret Harte and Mark Twain. This voice is heard especially in "The Gift of the Magi" as O. Henry writes,
While the mistress of the home is gradually subsiding from the first stage to the second take a look at the home...
- They also contain a "patterned structure" that was originated by Edgar Allan Poe as definitive of the short story. This pattern involves a problem that is often psychological; then there is "a reversal of Friendship." O. Henry's story "The Last Leaf" best illustrates this as Johnsy decides that she wants to die, but Sue and Mr. Behrman essay to prevent this. The little curmudgeon Behrman surprisingly makes the ultimate sacrifice as he paints a leaf on the window so that Johnsy will continue to want to live, but at the same time he contracts pneumonia and dies.