Aside from being the source of a delightfully distracting kind of strife that would be hard to give up, love triangles can conclude catastrophically.

FORBES: New American Slogan: Life, Liberty, and Love Triangles

In the history of love triangles, no one wants to choose.

FORBES: New American Slogan: Life, Liberty, and Love Triangles

Perhaps the most compelling storytelling convention with the least relevance to real romantic relationships, love triangles supply melodrama in literature, film, and television with little to no effort.

FORBES: New American Slogan: Life, Liberty, and Love Triangles

It is unusual for the FBI to get sucked into a case of cyber harassment and love triangles, but reports say Kelley had a friend at the agency who she originally complained to.

FORBES: Simple E-mail Trail Was The Undoing Of Petraeus

That Mr. Zulawski found a fertile subject early on in the fallout of desire and obsession is evident in two vivid shorts made for Polish television, both involving love triangles: "Pavoncello" (1967), based on a story by Stefan Zeromski, and "The Song of Triumphant Love" ("Piesn triumfujacej milosci, " 1967), from a tale by Ivan Turgenev.

WSJ: Andrzej Zulawski | Cinefamily | BAMcin��matek | Love and Madness

"The Last Station" was adapted from the novel by Jay Parini, and its structure is fairly intricate parallel love stories (Tolstoy and Sofya, Valentin and Masha), plus interlocking triangles (Sofya and Chertkov contending for Tolstoy's soul, Sofya and Chertkov pumping Valentin for information about one another's grip on Tolstoy's property).

WSJ: The Last Station and The Book of Eli | Review by Joe Morgenstern