Litany vs My mistress's eyes

Collins uses the same rhetorical techniques as Shakespeare, by not comparing his beloved to wonderful things or by creating beautiful imagery.  No.  Instead, they both compare their beloved to negative things.  Shakespeare basically says that his mistress does not have glistening eyes, golden hair or a goddess like posture and Collins says that Litany is not the moon or the stars, nor the pine scented air.  This draws the reader in, because when one thinks of a poem written about a woman, he would think that it would be a love poem, filled with sappy metaphors and comparisons.  These two poems totally defy that previous notion and makes it cynical rather than light hearted.