Common themes

Playwright David Edgar, in a fascinating piece in the Guardian, notes that the same summary can describe more than one play, film or story, thus:

A town is threatened by a malevolent force of nature. A leading citizen seeks to take the necessary action to protect the community from this danger, but finds that the economic interests of the town are ranged against him and he ends up in battle alone (Jaws, Ibsen's An Enemy of the People).

Two sisters are unjustly preferred over a third sister. Despite their efforts, the youngest sister marries into royalty and her wicked siblings are confounded. (The situation at the beginning of both King Lear and Cinderella.)

A husband and wife are at war. A younger influence enters their lives, providing a sexual temptation which threatens the marriage. But ultimately, they discover that, although they find it hard to live together, they cannot live apart. (A host of 19th- and 20th-century marriage plays, including Strindberg's The Dance of Death, Edward Albee's Who's Afraid of Virginia Woolf?, Noël Coward's Private Lives and John Osborne's Look Back in Anger.)

And, Edgar says, he's not the first one to spot the parallels between the tragedy of Hamlet and that of Diana, Princess of Wales:
With her father's encouragement, a young woman allows herself to be wooed and wed by a prince. Her brother moves a long way away. The prince behaves increasingly peculiarly, and, shortly after the death of the woman's father, leaves on board ship. The woman goes mad, alarms the royal family, gives everybody flowers, escapes from her minders, and dies in a suspicious accident. The brother returns, angry, at the head of a popular army. There is a contest over the funeral arrangements between family, church and state. The prince returns and he and the woman's brother end up fighting over the coffin.