Damn, I'm not really sure. Most of the bad movies out there I usually avoid, laugh at, or just watch a review or riff of other people watching it. One that comes to mind right now is The Last Airbender. At least with something like Dragonball Evolution I can laugh at it for how much it completely misses the point of the show. There was nothing to laugh at in The Last Airbender (besides the penis hair thing), it was just a pain to sit through. Horrible acting, dialogue composed of mainly exposition, crappy effects, a lack of any character depth or humor, and just plain boring. Granted, I'm not a big enough fan of the show, although I do enjoy it, that it pisses me off, same with Dragonball Evolution. Now, if they were to make a live-action film of something I love, like Death Note (which I'm fully aware they're making), Evangelion, Madoka Magica, or even somehow FLCL, and those turned out to be really, really shitty, then I'd have a reason to throw a fit.
Another one that comes to mind is Tim Burton's Chronicles of Narnia, oh...wait, sorry, I mean Alice in Wonderland. Like Dragonball Evolution, it misses the entire point of the source material, in favor of having big epic battle scenes that Alice in Wonderland never had and a coherent plot to a story that doesn't really have or needed a coherent plot. It puts logic and reason into a world that's not suppose to have any logic or reason. It's even sadder since a lot of the designs, characters, and overall look of the film would've worked fine if it were a much more faithful adaptation, and Tim Burton seemed like an ideal choice to direct an Alice in Wonderland movie, whether it really was his fault or if there was a lot of studio interference, although his track record hasn't been great as of late.
I'm sure there's more movies I've seen that's probably worse, but I mostly specialize in bad anime rather than bad films.