Melody-wise my favorite pop song by the Floyd. I assume the lyrics were meant as mockery of Disco. Had Waters written upbeat lyrics, who knows, it might have been a chart topper!
That's a great one. The film version of the song is even darker, if I recall.
How about Bobby Vee, "The Night Has a Thousand Eyes"? The music is super-upbeat, but the lyrics are essentially saying, "If you cheat on me, I'll hear about it, and I will mess you up." It's implied.
Bang! Bang! Maxwell's silver hammer Came down upon her head Bang! Bang! Maxwell's silver hammer Made sure that she was dead
A Paul McCartney song, the rest of The Beatles hated it. Especially in view of what was apparently tortuous recording sessions. Personally I've always liked it!
But if that's not upbeat music with downbeat lyrics I don't know what is!
I've been living in style Unaccustomed as I am To the luxury life I've been hitting the town And it didn't hit back
I've been doing the rounds Unaccustomed as I am To the time on my hands Now I don't have to tell anybody When I'm going to get back
Ever since you went away I've had this sentimental inclination Not to change a single thing As I pull the sheet back on the bed I want to go bury my head In your pillow
Now that I'm alone again I can't stop breaking down again The simplest things set me off again And take me to that place
Where I can't find my brave face Where I can't find my brave face My brave, my brave, my brave face My brave face
I've been living a lie Unaccustomed as I am To the work of the housewife I've been breaking up Dirty dishes and throwing them away
Ever since you left I have been trying to Compose a "Baby, will you please come home" note Meant for you As I clear away another untouched TV dinner From the table I laid for two
Now that I'm alone again I can't stop breaking down again The simplest things set me off again And take me to that place
Where I can't find my brave face Where I can't find my brave face My brave, my brave, my brave face My brave face
Witchfynde ~ "Would Not Be Seen Dead in Heaven" (1980)
Well there's one place that I don't wanna go And even if I went there There'd be nobody that I know No, I can't see myself with halo & wings I wanna go below where they do horny things
You know, I would not be seen dead in heaven You know, I would not be seen there at all You know, I would not be seen dead in heaven You know, I would not be seen there at all Not a chance, no way, no how
If heaven's so great, then why don't you go I'd rather fry, than be part of your show I'm not a little angel I never will be I'm not a little devil, not yet, but I could be
Repeat chorus
Up there chasing pretty angels, is just no go Instead of arrows I'd rather shoot my cocoa Don't wanna join their choir, I wouldn't get far I'll form a helluva band, and play lead guitar
Blue Öyster Cult ~ "Fire of Unknown Origin" (from the 1981 album of the same name)
Death comes sweeping through the hallway Like a lady's dress Death comes driving down the highway In its Sunday best
A fire of unknown origin Took my baby away A fire of unknown origin Took my baby away
Swept her up and off my wavelength Swallowed her up Like the ocean in a fire So thick and grey
A fire of unknown origin Took my baby away A fire of unknown origin Took my baby away
Death comes driving I can't do nothing Death goes There must be something There must be something That remains There must be something… There must be something…
A fire of unknown origin Took my baby away A fire of unknown origin Took my baby Took my baby away
It's implied. 
