"...the radiance burnt through, the revelation, the religious feeling!- when Old Joseph and Peter faced them: "Star-gazing?" said Peter. It was like running one's face against a granite wall in the darkness! It was shocking; it was horrible!"
Here the contrast between how Clarissa felt for Peter and how she felt for Sally. The feelings that arise within Clarissa when Sally kisses her are ones of joy and elation but the moment Peter speaks, those feelings are gone. Woolf makes it very clear that Sally is airy and exilarating part of Clarissa's young life while Peter is the harsh and abrasive part. What is interesting is that Clarissa clearly loves both of them even though they are so different. They represent different things to her, but Clarissa is still able to love them in very different ways.