In the theatres, the worst had to have been War of the Worlds. Omgosh, the running, the screaming, the crying...... on and on....... and that was just from ME because we went and paid $12 a piece to see it and missed the magic "half hour walk out and you can get your money back".
On Tv, the running joke around our house are those natural disaster movies, like Atomic Twister, that are replayed so much you inadvertantly, eventually, see the whole movie just by channel surfing by for those few weeks.
On DVD, well, I admit it. Last weekend in a fit of boredom I rented some stupid movie called Absolute Zero (a very cheap, low-budget, knock off of The Day After Tomorrow, which, btw, was bad enough on it's own and shouldn't have been emulated). It went on and on, then sort of suddenly stopped. Almost as if they ran too close to their buck-fifty budget and had to just end it. The only thing I got out of it was the realization as to why some movies go straight to video.