We're goin' back in time!

I am going to spare you the babble about how Kevin's Movie Blog is so popular, we bought a Time Machine and just get into the topic. My sister asked me yesterday an interesting question that I think would spawn some interesting answers. "If you could go back in time and stop any movie from being made, which one would it be." Now, you can think of the butterfly effect if you wanna get all deep and philosophical, or you can just respond with a movie that you thought was so incredibly terrible, it would actually do the world good if it didn't exist.
Is there a movie that would align the planets, allowing for meaningful communication from extra terrestrials to common household pets and bring about world peace? (By the way, that bit was from Bill & Teds Excellent Adventure, and if that is your answer...it's on!)
Now, I thought long and hard about this... ... well, ok, you got me, I thought about it for a matter of 2 minutes, but I really concentrated... ... fine, it was while I was inflating a tire and carrying on a conversation, but I am really good at multi tasking. Anywho, my answer surprised me, but hear me out.
The answer is Star Wars Ep. 1. Now, let me preface that by saying I am a huge Star Wars fan, according to the movie Fanboys, I would pass any trivia test they can throw at me, but the reason why I would kill this is due to the fact Ep. 1 tainted the entire 6-tology. Now, the first reason you can think of is Jar Jar Binks, and that is not correct, in fact, I think Jar Jar has his place (more on that later). I think the movie was by far the most inferior, it tainted the image of Darth Vader, by showing him as a little annoying kid. He went from a feared badass with a bone chilling breathing sound to a kid who has a crush on Natalie Portman and can fix anything. As I have said before, you don't need to know everything that made the monster, sometimes just that he is evil is good enough, and usually more terrifying... ...forget making him human and justifying his later monstrous actions.
The film also showed the then "Immortal George Lucas," at that point, a god among men a truly flawed movie maker. No matter what would come after this, the newer trilogy would never recover and always have a tainted image, and the one flaw in an otherwise great set of movies.
Now, which would it be for you? Is it Dude Where's My Car? or maybe you would stop Saw and end the torture porn subclass before it ever got started? Let me know!
Until then, movie geeks, stay cool!