In Shakespeare's sonnet 130, what is the tone and how does it affect the reader?How is tone created in a poem, and how does it affect the reader?

The tone is sometimes considered a subjective appraisal of
a poem or other written work, since it can be something that a reader picks up on in a
subtle way, and not necessarily spelled out in a clear and direct fashion.  The tone
conveys the mood of the poem.

For me, the tone of sonnet
130 is mocking.  This is an interesting sonnet, in that even though the speaker is
describing his lady love, he seems more concerned with slamming the cliched descriptions
usually used to describe a love in poetry.  I've highlighted the cliched descriptions of
eyes, lips and breasts that Shakespeare mocks in his opening
lines.

My
mistress's eyes are nothing like the
sun;

Coral is
far more red than her lips'
red;

If snow be
white, why then her breasts
are dun;

If hairs be wires, black wires grow on her
head.

This last description
for me, tips the scale to a sarcastic mocking tone.  It's very hard to receive, as a
reader, the description of "black wires" for hair from a poet who is sincerely pouring
his love for his lady's beauty into his description.  His implication in choosing "black
wires" seems to be the most opposite of whatever trite phrase most poets would use
(Black as coal?  As a raven?) would be.

His reasoning in
defying these celestial, cliched descriptions becomes clear when he 
says:

I grant
I never saw a goddess go;

My mistress, when she walks,
treads on the ground.

His
mocking, however, turns to a defiant and protective tone in the final
couplet:

And
yet, by heaven, I think my love as rare

As any she belied
with false compare.

He makes
it clear that he needs none of the false and trite comparisons to prove how deep and
true his love is.