I have been trying to find this book for years! It was written by a popular 80s/90s YA author (like Lois Lowry but I don't think it was actually her). It was a compilation of maybe 4 or 5 shorter stories all put together in one book. The only story I remember was about 2 teens, a boy and a girl, who were best friends. They did everything together, and one of them (the girl I think?) had unrequited feelings for the other one. They spent the night together camping, and they both had to get into the same sleeping bag for some reason, and being so close together all night long made the boy realize his feelings for the girl. But for some reason he didn't know how to tell her. And there was this overpass or bridge or something that they both kept making fun of throughout the story, because there was graffiti on it which some crazy guy had put up there declaring his love for a girl. And they kept wondering how he did it, did he hang upside down? And at the end of the story the boy went and changed the graffiti slightly to declare his love for the girl.

I loved this story and I would be so happy if I could find it again! If anyone recognizes it, I would greatly appreciate the information.