The curse of Queen Margaret in the movie King Richard III

Queen Margaret, the Queen of England before Edward IV took her husband King Henry VI's place, appears for only two scenes of the whole play, repeats herself a lot, and is generally a woman fermenting in her own misery, yet Shakespeare lets her lay the framework for the plot of the play. What's memorable about her is the bitter criticism and curses she calls out on other characters. She's so insignificant to the main players that their first reaction to her is, "What? You're still here?" The grief she feels is awful, and that she's unavenged adds insult to injury.

Worse than anything, Margaret feels irrelevant, and her unnoticed misery only fuels her wrath. Richard III enters and fights with Queen Elizabeth about his loyalties and intentions. Queen Margaret shows up and curses Edward IV to die of sickness; Edward V to die young; Queen Elizabeth to live long, and be not wife, mother, or Queen; Rivers, Dorset, and Hastings to die an unnatural death; Richard III to be friends of traitors and betrayed by friends and Queen Elizabeth to later wish for Margaret's help to curse Richard III. Margaret spares Buckingham telling him he hasn't wronged her, but he insults her so she curses him too. Queen Elizabeth tells her son Dorset to leave England to see Richmond (Henry VII), after Stanley brings news that Richard III plans to crown Anne Neville queen, fulfilling Anne's own curse that Richard III's future wife be cursed and miserable.

While she herself has been immensely cruel, she feels utterly powerless now, and her rage is emblematic of the impotent misery that all of Richard's victims feel. She was caught in the last iteration of his treachery (when he killed her husband and son), so she ...