Reasons for Sibling Homicide

I'm going to kill my sister.

OK, you probably need a bit more information. For a few days now, pretty much since the commercials started, she's been bugging me to go see "Vampires Suck". She wore me down and I agreed to go see it. I had to go to the library yesterday, so I invited her to go afterwards.
I just...I don't know where to begin. It's a bit hard to make fun of the Twilight movies because they are ridiculous all on their own, so I really can't blame the parody too much. But seriously, did this movie really need to exist? I could have happily lived out the rest of my life without having experienced it. Again, the same goes for the whole Twilight thing.
And people were actually laughing all the way throughout! It was not funny, none of it! Halfway through I was seriously considering how I could manage to hit myself unconscious so the time would pass quickly.
I will give my sister credit in that she also did not laugh once. As soon as the credits began she and I made a bee line for the door, regardless of the little clips in between the names. That, at least, calmed my urge to throttle her for making me sit through that.
The one thing about the movie that was moderately amusing was how the main actress did a perfect imitation of Kirsten (or however the hell you spell her name) Stewart's psychotic mannerisms.

Please, I urge you, do not, I repeat DO NOT see this movie.