At the Library song meaning

In this song the narrator is describing his indecisiveness and shyness as he's trying to talk to a girl he likes. He keeps looking at her from a distance and day-dream wondering why he likes her, what it is about her that seems to charm him. He's trying to make himself finally talk to her, but in the end she walks away with her boyfriend, leaving the narrator one-on-one with his thoughts. He's upset, but then again, he knows he probably would have never had the guts to talk to her, and so he lets his feelings towards her rest till the next time he sees her and goes through that doubt and insecurity all over again.

There is a theory that in this song the author is talking about an ugly girl that he thought he had a chance with, but in the end even she turned out to have a boyfriend. However, the lyrics show that he's truly fascinated with the girl, and the words "What is it about you that I adore?" most likely express the narrator's positive interest and awe rather than surprise and doubt. He wants her and doesn't know why, and doesn't have the courage to express his feelings.