In Shakespeare's play, Macbeth, one of the major themes is that of appearance versus reality, specifically in the guise of deception. There are many things that are not as they appear.
The witches appear to visit to simply tell Macbeth's fortune (and Banquo's). However, their true intent is to trick him into forfeiting his soul to the "powers of darkness."
Lady Macbeth welcomes Duncan to their home, having told him that she has paid attention to every detail so that his visit is a memorable one.
[In] Act I, [Lady Macbeth] "humbly" tells King Duncan that she has eagerly awaited his arrival and that her preparations for it are "in every point twice done, and then double done" (l.vi.14-18). The irony here is that double-dealing and falsity are at hand, and Lady Macbeth's ability to conceal her intentions while at the same time making hidden reference to them [is startling].
Appearance versus reality, or deception, is seen in Lady Macbeth's advice to her husband:
Look like the innocent flower, / But be the serpent under't (65-66)
We also see appearance versus reality when Macbeth acts like an old friend with Banquo, while he is already planning his murder, as well as that of his son Fleance.
Lady Macbeth takes Macbeth to task when it seems as if he is going to change his mind about carrying out the murder of Duncan. She refers to his change of attitude or intent like the changing of one's clothing—as if he hid his true feelings when he really had no intention of following through.
Was the hope drunk
Wherein you dress'd yourself? Hath it slept since?(40)
And wakes it now, to look so green and pale
At what it did so freely?
This comment reflects the idea of appearance versus reality or deception. Lady Macbeth is basically asking if he was lying to her, hiding his real intent as one might put on a disguise.