How is the theme of guilt used in Macbeth?

There are a few ways that the theme of guilt is conveyed
in Macbeth. Perhaps one example that is overlooked when it comes to
illustrating guilt is Lady Macbeth's quote:

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Come, you
spirits

That tend on mortal thoughts, unsex me
here,

And fill me, from the crown to the toe, (I.v.
40-42)

Lady Macbeth feels
guilty that she is not a man.  During the play, gender plays an important role.  Lady
Macbeth thinks that Macbeth does not have the backbone to do what needs to be done to
gain the crown.  So, she asks the spirits to "unsex" her so that she can
become male so as to gain the crown; something she does not think
her husband is really man enough to do.

Therefore, Lady
Macbeth feels guilt in the fact that she was not born male given she has the male
mindset needed to gain what she believes Macbeth cannot.