Even if Margaret doesn’t like Philip all that much, it’s still exciting when she gets to kiss him. Her reaction suggests that she wants to kiss him because she’s excited and because it’s something all the other girls seem to want, not because she actually has feelings for him. And though Margaret doesn’t care for Norman, it’s also a sign that perhaps he’s not so bad when he does exactly what Margaret asks him to (unlike, perhaps, Philip when he was in the bathroom with Laura).