Sonnet 130 is one of Shakespeare's well-known sonnets also called My Mistress' Eyes. He popularized the Elizabethan sonnet which has a different emphasis from the original sonnet form which Petrarch favored. Instead of the Petrarchan or Italian sonnet, the Elizabethan or Shakespearean sonnet has three quatrains (four lines each) followed by a concluding rhyming couplet.
In My Mistress' Eyes, Shakespeare deliberately mocks the traditional love poem although he uses exaggeration in equal measure whilst trying to give an objective account. However, he seems to exaggerate his lover's faults not her qualities. The eyes have long been written about but Shakespeare begins his sonnet saying that her "eyes are nothing like the sun" setting the reader up for this seemingly cruel and unflattering description. All the stereotypical female attributes such as the lips, the cheeks, the hair and the breasts have attention drawn to them but they leave the reader with a visual image of an ungainly woman with very little to admire. Even her breath "reeks," although this can be modified by the reference to perfume suggesting that it is not necessarily that her breath smells unpleasant but it certainly doesn't smell sweet whereas presumably in any other situation, the woman's breath would gratify the senses. Certainly, in poetry, the poet is unlikely to draw attention to her shortcomings.
It seems that Shakespeare uses this sarcastic tone to ridicule the insincerity of more traditional sonnets which have ridiculous notions about a woman's virtue. He parodies the style of commenting on his lover's features but surprises the reader with his rude and unkind comparisons. She cannot sing and is certainly not dainty and light of foot. However, he does redeem himself when in the couplet he admits that she is "rare" and it would be unreasonable to compare her to anyone because her beauty is immeasurable and any comparison misleading or "false." In discussing the theme of love then it is apparent that Shakespeare intends for the reader to grasp an understanding of beauty and love as far more than physical appearance.
Shakespeare's "Sonnet 130" is a parody of other typical sonnets that made over-the-top, flowery comparisons of beauty to the poets' beloved. Shakespeare employs many of these comparisons in his poem: comparing eyes to the sun, snowy white complexions, roses in cheeks, perfumed breath, goddess-like attributes; but the difference is that Shakespeare claims his mistress has none of these attractive features. In fact, in lines such as "If snow be white, why then her breasts are dun" the reader learns that the very opposite is true.
Shakespeare uses the typical conventions to poke fun at his contemporaries. Of course, his mistress has none of those prized features, but Shakespeare praises her for different, more important reasons in the final lines, "And yet, by heaven, I think my love as rare as any she belied with false compare (lines 13-14). In the end, any false comparisons for the sake of poetry would be meaningless. His mistress' unique qualities are what endear her to him.