They thought witches were real in his time, so they were a natural predictor for telling the future in his plays.
In Act 1, Lady Macbeth is the planner, the one who is dragging her reluctant husband into committing one murder. But by Act 4, Macbeth commits murder after murder and Lady Macbeth is the reluctant one, nauseated and consumed with guilt by the bloodshed. The roles actually reverse much earlier in the play, when Macbeth kills the grooms. That was not in Lady Macbeth's plan, and she is horrified by it.
Macbeth believes he has to kill Duncan's guards in case they heard anything happen in the room while Macbeth was killing Duncan.
Supernatural elements can help advance the plot of a story by creating conflict.
That she has a softer side, although she rarely shows it
(Apex)~ Supernatural Elements
they give away just enough information about the story's events to keep the audience interested in finding out more.
(Apex Learning) They are afraid they will be murdered by someone close to them.
By playing on audiences fears
Banquo's ghost, which shows up at the dinner party the Macbeths are throwing. Only Macbeth can see him.
she speaks in rhyme.
"Come, let me clutch thee. I have thee not, and yet I see thee still."
Audiences during Shakespeare's time considered witches and curses to be real and much scarier than todays audiences would.
killing king duncan (:
ghost and curses
art thou afeared / to be the same in thine own act and valour / as thou art in desire?