I plant my feet and jerk my neck and torso back and forth to songs about murder, vengeance, being pissed off with someone, rape, war and prostitution (A7X, A7X, Linkin Park, Rammstein, Iron Maiden and Iron Maiden, respectively) and see nothing wrong with it. If the music's good that's all that matters.

Der Meister by Rammstein is about the apocalypse but it seems like a fairly happy song
Quoted for partial truth. The full truth is that it's an extremely cheerful, euphoric, ecstatic song and I love it.

Point is, I don't care what the song's about. If I can get into it I don't mind.