This does seem to be a list of "movies I dislike" rather than "really bad movies".
..So in that spirit, I'll nominate Meet Joe Black.
It was obviously an attempt to recreate the romantic fantasies of the golden era and garner a load of Oscars. Anthony Hopkins does give it a bit of gravitas, but that's about as good as it gets.
Brad Pitt plays Death. That's right, the Grim Reaper, for reasons too tedious to relate and which I can't remember anyway, is granted human form as a stoned beach bum, emerging puppy-eyed from a three week stint in his basement. I think they wanted Keanu Reeves but he was busy making the Matrix.
It resides in my memory as endless scenes of Brad Pitt being lonely and sad because he's Death.
It wasn't, in a lot of ways, a bad movie. At heart it's not such a bad idea, it looked good, and it has some half-decent actors in it. But what grated about it was the aching sincerity, which the movie couldn't justify. It really wanted you to believe in this sad Death figure, eternally separated from humanity. Of course he's cut off from humanity, he's Death! Nobody's inviting him around for a few beers in front of the football. Especially not the sad figure that Brad Pitt portrays. To prepare for the role he must have spent weeks down at the high school watching the gloomy teenagers fail to crack a smile.
The choking seriousness might have been undercut by a hint of wit - even a hint of a hint - but I reckon the director was too caught up in the profundity of his movie to allow a whisper of a smile to touch his face. Laughter was banned on set, as were bright colours, so that nobody forget that they were making a serious movie.
If there was a Gloom award for the Saddest Movie of the Year, this wouldn't even have turned up. It would have been sitting in a darkened room contemplating its own sadness and loneliness.
It would have been a better movie if they'd chucked in a few aliens. or turned it into Silence of the Lambs II, with Anthony Hopkins slaughtering and munching his way through the supporting cast.
And it's about a million years long.