The phrase "things base and vile" is found in the first act and scene of Shakespeare's A Midsummer Night's Dream and quoted by Helena during her soliloquy on love. Not only does Helena discuss love, but she discusses how fickle and unfair loves seems to be. Helena first wonders why some people are happier than others in love. She wonders about what characteristics must be held by a woman in order to find and to sustain love.
First, she focuses on physical attributes and argues that she is just as pretty as any other female in Athens. But this does not help her to find love with Demetrius if he doesn't think so. She then discusses how a person in love tends to see things differently than everyone else: "Things base and vile, holding no quantity,/ Love can transpose to form and dignity" (I.i.236-237). The "base and vile" part refers to how a person's common or plain looks (or even disgusting looks) seem to become beautiful in a lover's eyes. Helena concludes that love can be compared to a child who is easily tempted and fooled because Demetrius once showed her love before he saw Hermia.
Naturally, Helena believes that Hermia is more beautiful than she is because she knew Demetrius before he saw Hermia--then everything changed! The discussion about love goes on from there, but it is certainly interesting that Helena discusses a great human truth that even things that might seem ugly to some can be considered beautiful to those who see through the eyes of love.