Lyric discussion by alterEgo 

i dont think she is being sarcastic, i think she is genuinely thanking that person. She mourns the loss of the relationship, and also to cope with it, she writes love songs. Theres a significant difference between the clean version, and the dirty version. The clean version is more she is feeling depressed, whilst the dirty version, which is titled "Another fucking lovesong' reflects anger and resentment towards the other. Maybe sarcasm is applicable in the other version, but I certainly don't think it belongs here.

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