In The Outsiders, how does the quote "It seemed funny to me that the sunset she saw from her patio and, the one I saw from the back steps was the...

The sunset is a metaphor for how everyone is more alike than different.

The Outsiders is largely about distinctions between social classes. The greasers are the poor kids, and the Socs are the rich kids. The groups do not meet, unless it is to fight.  They do not feel as if they have much in common and they do not make an effort to understand one another.

When Pony meets Cherry and her friend at the movies, he spends time with Socs for the first time. Pony has never really interacted with Socs outside of school, where he often has classes with them because he is smart. He unexpectedly finds that he likes Cherry, and she seems to like him and Johnny.

Cherry is aware that Pony is a deep thinker. She is impressed with his thoughtfulness and reflectiveness.

She kind of shrugged. "I could just tell. I'll bet you watch sunsets, too." She was quiet for a minute after I nodded. "I used to watch them, too, before I got so busy..." (Ch. 3)

Pony has a realization about the Socs when he meets Cherry. She tells him that everyone has problems, even Socs. The greasers usually think that the Socs have everything going for them, because they are wealthy and have a future laid out. Cherry helps Pony realize that life as a Soc is not perfect.

"I'll bet you think the Socs have it made.  The rich kids, the West-side Socs. I'll tell you something, Ponyboy, and it may come as a surprise. We have troubles you've never even heard of. You want to know something?" She looked me straight in the eye. "Things are rough all over" (Ch. 2).

Socs still target greasers, and do not approve of those Socs who mix with them. Cherry’s boyfriend Bob and his friends almost start a fight when they see Cherry with Pony and Johnny. Cherry avoids the fight, but they return later. Bob is drunk and mean, and almost drowns Pony. Johnny saves his friend by killing Bob. Things are rough all over, all right.

This quote highlights one of the themes of the book, that you never really know what is happening with another person. You may think you know what a person's life is like, but you can never really know unless you are in the person's shoes. This quote is about empathy, which is one of the major lessons Pony learns through his interactions with the Socs.