This one is tough - I know there are lots of songs I dislike, but few that I absolutely can't stand, at least not with the passion that Daphne hates "What's Up." There's a song I hate so much that I have actually blocked it from my memory - at least, I can't think of what it is. I think there's a woman singing - if you can call it that.
I also find that lots of songs grow on you with repeated listening. I used to really hate "What I am" by Edie Brickell and the New Bohemians, but now I actually like it. Funny thing is, I like it for exactly the same reason I hated it when I was 10 - it's quirky and unexpected.
In any case, I'm going to take the easy way out and just choose the song that caused my friends and I to flee screaming out of school dances in high school: "Achy Breaky Heart" by Billy Ray Cyrus.
Maybe that was a little drastic, but that was part of the fun. In any case, Weird Al, as always, nailed it.