For a charm of powerful trouble, Like a hell-broth boil and bubble

Macbeth, to me, is Shakespeare's darkest play. Terror, violence and dark magic permeate the story, inspiring some of the most frightening lines Shakespeare ever wrote. 

The anxiety in Macbeth never lets up, and the more you pay attention the more uneasy you feel. In the end you can't help wondering what was choice, and what was preordained for Macbeth and his wife. 

Many say that King Lear is Shakespeare's darkest play. I disagree. While Lear is brutal, there are glimmers of redemption in the play—and, more importantly, through its tragedy it teaches us much that is not obvious about love. There is no redemption in Macbeth. None whatsoever.

In the past, superstitious actors have refused to utter the name "Macbeth" inside a theater, referring to it instead as "the Scottish play." This superstition is parodied in the Canadian comedy series Slings and Arrows in a conversation between the theater director and the late-night Nigerian janitor:

Janitor: "That play is evil. It teaches us nothing."

Director: "Well it...  it teaches us about evil."

Janitor: "NO! It shows us evil... It teaches us nothing."

The exchange is wonderful. But while the janitor's comeback is clever, it's not exactly true. 

We don't have to be taught a lesson in order to learn a lesson. Sometimes we learn in the absence of instruction; in the void, in uncertainty, or in the presence of mystery.

Macbeth is that kind of abyss.