Santa Baby by Madge is still the most hated and detested, but that obnoxious f-ing song by the Pretenders where Chrissie Hynde just whines and whines is moving up fast.
They played it CONSTANTLY at Bath & Body Works when I worked there for a minute. Oh, it's called "2000 Miles" which is how far away I want to be when this crap comes over the sound system.
Side note, I didn't know "Mary Did You Know" so I looked it up on youtube and yes the comment is true, at 1:26 Jesus is wearing shades. I LOLed.
http://www.youtube.com/watch?v=mN70R-3ao0U
Threaded Mode