Macbeth thinks that people spend their lives 'strutting' and 'fretting.' Discuss the significance of word choice.

The use of terms "struts" and "frets" helps to describe
the actions of a bad actor.  Macbeth is at a point in the narrative when his
descriptions of being in the world are littered with images of emptiness and futility. 
In a way, these images help to describe his own "strutting" and "fretting" in terms of
all that he did to gain an illusion of power and control.  When hearing of Lady
Macbeth's death and confronted with the realization that all he has done has been in
vain, Macbeth understands the true nature of existence, his true nature of existence, as
one of emptiness.  To that end, he employs the image of the "poor player," or actor who
overdramatizes everything he does on stage with his "struts" and "frets."  Macbeth makes
the argument that the exaggerated actions of the actor is nothing more than confirmation
of his uselessness and his ineffectiveness.  The ultimate statement of this condition is
that the hyperbolic actions are "heard no more" once the acting has passed.  This
reflects the transitory and passing nature of life, one that has demonstrated itself to
Macbeth and his own experiences in his narrative.