Lyric discussion by price1207 

Cover art for Cubicles lyrics by My Chemical Romance

this song is about obsession and rejection. he used cubicles as a metaphor to any situation where every day you see the same girl and fall in love with her. "It's the tearing sound of love-notes Casting out the gray stained windows " means that he writes love notes to her, but never has the nerve to give them to her, so he throws them out a window. basically the song is about loving someone who you see every day but doesn't even notice you exist.