The cruelest torture I can imagine would involve being forced to go through life with a 24/7 soundtrack consisting of:
Clair, by Gilbert O'Sullivan - heartfelt pedophilia at its finest!
Brand New Key, by Melanie - she's got ROLLER SKATES, and you've got a KEY. Nudge-nudge, wink-wink.
I Am Woman, by Helen Reddy - if she's still an embryo, with a long long way to go, why does she insist on singing to us now, instead of waiting until she grows up into a human being with a semblance of musical talent?
There are probably other candidates, but for someone I really hate I wouldn't want to lessen the suffering any by adding too much variety.
What songs should YOUR worst enemy endure?