Well, love or lust!
This is one of the things that put me off pop music and attracted me to instrumental music as a kid, and to punk bands a bit later in life. As Chumbawumba once put it; "I hate the way that love songs have been made meaningless by endless, mindless repetition." (I can't remember the exact lyric, but that was the gist.)
As a musician and former song-writer, I could imagine writing a song about a particular love of my life, as a personal romantic gesture between just the two of us; but there's no way that I would ever have written a generic "love song" for public consumption.
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When you are fighting an invisible monster, first throw a bucket of paint over it.