[Matrixbeast]

Bio Dome. Pure trash. I was way too young for this movie (Thanks, HBO), but it did teach me a valuable lesson: Stoner comedies will never be good.

Dragonball Evolution. Goku is a high schooler? Ki is Airbending? Oozaru was formerly Piccolo's slave? WAT

The Room. "It's so bad it's good!" I disagree. It sucks. Hard. There are funny moments to take away from it, no doubt. But to sit through it all, it's hard to find a laugh when not riffing it with someone.

Starkid. Don't watch this movie. Please, don't watch it.

The Guyver. *Gags*

Scott Pilgrim Vs. The World. Let's take Scott Pilgrim, loud, brash, hot headed, and a total smartass, and cast an actor known to play shy, sheepish characters, make him bring aforementioned sheepish acting style and make a horrible love story out of it, but color it with video game references so people will like it! Let's remove the complexity of Scott's relationship with Ramona until the very end so it seems for 99% of the movie he's doing it just to bone her, and have him conveniently forget he already has a girlfriend for half the film's runtime, making him seem like a gigantic douche in the matter!
I hate this movie, especially after getting to read some of the comics. Fuck it. I think it's terrible because they misrepresented the characters and watered things down too much so characters are way too shallow.

Human Centipede. Like Bio Dome, pure trash. As a gore and snuff style horror flick, I've seen better. It's inconsistently shot and it's just eye rolling.

Special mentions:
Snow Dogs and Kangaroo Jack - Both for having scenes involving talking animals solely for trailer footage, despite both scenes barely lasting a minute or two, and, likewise, both during hallucinations AND only happening once in the movie. Listed here because neither movies were downright terrible, but they pissed me young off and I hate them for it.

Everything by Friedberg and Seltzer. Taking what little heart and weak comedy the first two Scary Movies had and completely removing them, their shit is almost literally just a feature length Family Guy episode, except replace tolerable animation with shitty props that would make 70's toku and early Doctor Who look high quality.
I only put it as a "Special mention" because 1. No way in hell I'm watching any of their shit after suffering through Meet the Spartans and 2. I'd rather not pad out my list by just throwing all their movies here