A fair amount of Contemporary Christian, or Christian Rock, songs serve as love songs of sorts. Most of these are actually written with God or Jesus as the target of the lyrics, although some of them can double as a song to a more human loved one. "Who I Am Hates Who I've Been," by Relient K, is actually more of a song directed to a person the author has wronged, although it could serve as a statement of repentence to God as well.
The song is an apology for past weaknesses and misbehaviors. The regret in the lyrics of this rather up-beat, somewhat pop-ish song is apparent specifically in the chorus: "I'm sorry for the person I became./I'm sorry that it took so long for me to change./I'm ready to try and never become that way again/'cause who I am hates who I've been."
An apology, an anthem of regret and a statement of repentance for past transgressions... which still holds the promise of hope, of being ready to change and not look back.