I have to second 2001: A Space Odyssey... I mean there have been plenty of crap movies that I've long since forgotten or don't care to even waste breathe talking about. 2001 stands out though because it's so incredibly overrated that I was about blown away about how bad that movie sucked when I finally saw it.
The move is well made... don't get me wrong. The special effects... many hold up even by today's standards. The space scenes look fantastic for how old it is. That is all the praise I can give it though. As movie, it is just one big ball of suck. It was so fantastically boring and nothing happened. I honestly could not believe they wasted literally 20 minutes showing us a lunar lander landing on the moon. It was so funny cause like... "FINALLY!!! The surface of the moon!!! It's gonna land soon!!" And then it was like... the ground opens up and it keeps on going down, down, down into some space station deal. Ho.. ly.. crap... Not kidding... 20 minutes... time it.... you watch a spaceship land to some ballet music. That was the most memorable part of the movie but there were plenty of other places where you literally sit there for minutes watching nothing happen and listen to music.
I was bored stiff by the end of that movie... I had to attend physical therapy to regain muscle strength and movement. I don't I've ever been so blown away by a movie than I was when that was over... I was like... Seriously?!?? SERIOUSLY?!!?! THAT WAS THE MOVIE?!!!? I mean... it's considered some great classic. And it wasn't like I wasn't expecting it to be anything super. There have been plenty of other old classics I watched knowing they were classic and they just didn't ring my bell. This? This was... just thinking about it I still cannot believe... it's just... yeah. If you need help falling asleep, turn that on, no joke, you'll be out like a light.
Yeah there are movies that are made worse or bad or whatever.... but most of those that are that bad you expect them to be bad when you turn it on. I think 2001 takes the cake for worst "good" movie I've ever seen. Definitely 3 hours I wish I would have spent doing something else (I thought was almost over at 1 hr and a half but no, I still had another 90 agonizing minutes to go).