“O, she doth teach the torches to burn bright.”

Coming at number one on that list of the most famous quotations from Romeo And Juliet is “O, she doth teach the torches to burn bright.” First, consider Romeo's comments in context: he is with his buddy Mercutio at the Capulets' masked ball. Mercutio has just informed Romeo about Queen Mab, a fairy who enters young men's dreams and makes them dream of love and passion. Romeo sees Juliet at the masked ball and falls in love with her right away; she, too, falls for him. Romeo's initial reaction to clapping eyes on Juliet is, “O, she doth teach the torches to burn bright.”

When Romeo first discovers Juliet dancing with a knight, he says these lyrics in appreciation of her. It's worth pausing to consider this image. "O, she doth teach the torches to burn bright": the torches don't appear to be all that light when compared to Juliet's beauty's brilliance and radiance. Teach here has the same connotation as teaching someone a lesson or schooling someone: it has a competitive ring to it. Romeo is implying that Juliet might teach the (poor, dim) torches a thing or two about how to glow brightly.

Romeo - Act 1, Scene 5.