Cherry gives us this answer at the end of her first meeting with Ponyboy after the movies. Even though she has had an amazing time talking to her new friend and they have both discovered that they are extremely like-minded, Cherry remains realistic about the social restrictions between greasers and Socs. She quietly tells Ponyboy:
"if I see you in the hall at school or someplace and don't say hi, well, it's not personal or anything, but..." (45).
Hating the reality of her words, but realizing the truth of the matter, Ponyboy immediately understands, even though he wishes he "was dead and buried somewhere. Or at least had on decent shirt" (46). He is embarrased by the social gulf between a really nice girl like Cherry and his greaser persona. At the end of their conversation, Ponyboy reminds Cherry not to forget that some greasers watch sunsets too.