The protagonist’s relationship is over and he can’t accept it. He continually calls his former love but she won’t pick up. He shows up to her house and looks at her through a window, wishing that he was her mirror so she would look at him and catch her fondest gazes again.(restraining order much?) I have loved this song for 40 years but never understood the mirror part. I always thought THE WOMAN was dreaming that the looking glass was him, which didn’t fit the narrative. I just realized, HE’S the one wishing the mirror was him...not her. Now this verse fits the rest of the song. If you’ve ever had your heartbroken, you can relate. Far too many stars have fell on me.