For me, music scores are a big part of a movie's atmosphere. Even just a really good score alone can elevate a movie for me.
On the other hand, there's some scores I've heard that are just so downright horrible that you wonder how they were ever conceived. These are not scores that are merely just generic or forgettable, but memorably terrible for poor compositions, and/or not fitting the on-screen action. It should be no surprise that many of the movies on his list are also terrible for reasons other than just the music.
Not accepting any suggestions, but I'd be curious to hear what some of you guys think are the bottom of the barrel.