Well, I can tell you why I hate Twilight.
It's poorly written, I find the characters are one-dimensional, and I have a theory on why this book is loved by so many people(which makes me hate it even more): Stephenie Meyer understands that every girl dreams to have this perfect guy just show up and say, "I'm so in love with you because you're so normal". Seriously - If Edward were really the guy he was in the books (basically flawless except the whole vampire thing, which he somehow managed to overcome) and Bella was the girl she was (completely normal and "flat"), they would not really be together. That's just not how it works in high school. The reason the books are so popular is because Stephenie Meyer could exploit that dream and use it to her advantage; she made Bella one-dimensional so that it wouldn't be difficult for the reader to imagine themselves as her, consciously or subconsciously.
The story isn't original, the "love" aspect isn't original, the characters are boring, it's poorly written - what's there to love?
d&f.