Personally...
Personally, I would have smiled after the first spike. And it would have been a real smile too, because I'd be thinking "Oh, I get how this works. I'm totally going to kill you all later." *grin grin*
Nice style. I didn't even notice the absence of colour or strangely cubical people until near the end.
(Also, yes, again insulting the disco ending. If you're trying to show how they just get on with their happy dumb lives, maybe something else - or without the music - would have been better. It just didn't end with the same impact it started with)