Why does Pony Boy remind Cherry that they both watch the same sunset?

In S.E. Hinton's novel The Outsiders, Ponyboy and Cherry talk about sunsets in Chapter Three. But Ponyboy doesn't remind Cherry that they both watch the sunsets, it's part of his thoughts after he talks with her. Cherry and Ponyboy talk about why their groups are so different (the Greasers and the Socs) and they come to the conclusion that it's about feelings. The Socs are cold and don't show their emotions, and the Greasers show their emotions too much. But in that conversation, they find out that they have things in common, as well. Ponyboy and Cherry both like to watch sunsets. Cherry shares that she thinks Ponyboy watches sunsets. She recognizes his sensitivity, and that's what she bases her assumption on. She also shares that she used to watch them, but then she got too busy for that. Here is the quote from Chapter Three where Ponyboy is thinking about the similarities between the Greasers and the Socs.

It seemed funny to me that the sunset she saw from her patio and, the one I saw from the back steps was the same one. Maybe the two different worlds we lived in weren't so different. We saw the same sunset.

You see here that Ponyboy is beginning to change his thinking regarding the Socs. Before, he thought they were as different from the Greasers as night and day. After the conversation with Cherry, he's thinking that they may have more in common than they previously thought.