1) It's poorly written. Stephen King can back me up on SMeyer being a horrible writer.
2) Those are not vampires, they're sparkly fags. And by fag, I don't mean gay, I mean fag.
3) Edward is a 107 year old virgin. Can you say pathetic?
4) Bella has no redeeming qualities; she's a very weak main character. Physically she isn't strong. She can't run away right even; she trips too much. She's not smart, either, she's almost brain dead (come on, how long did it take her to figure out Edward was a vampire again?). She's not very pretty. She's not nice; she treats her friends horribly, and wants nothing to do with normal boys who aren't monsters. Somehow, everyone loves her, despite all this, which only makes her even more dislikable.
5) There is no plot. Or, if there is, it was so small I missed it.
6) Edward is abusive and a stalker.
7) Bella has absolutely no opposition to Edward stalking her. (In Buffy the Vampire slayer, Buffy tells Angel that girls don't like being stalked. She actually had brain and knew that stalking isn't hot, even though Angel is. She doesn't like it when Spike stalks her, either. She's a slayer and even she's normal enough to know that stalking isn't a turn on.)
8) Love at first sight isn't real. I know a lot of other stories use this, but you can't know a person's soul, who they really are, by just looking at them. Sure, you can get some idea's that may or may not be right, but you can't actually know deep into that person.
9) Jacob never had a chance. There was no second in the books when I thought she might have possibly picked him.
10) The book contradicts itself. First, vampires can't have children because the sperm is dead or something. Then, Bella ends up pregnant. Okay, pick a story and stick to it, Smeyer! Either they can or can't have children, not both!
11) She almost kills herself after they break up after going out for like a month. Great family values you're teaching there, Smeyer.
12) Bella's a little brat to her father.
13) It's extremely boring. I don't know how I even got through them
14) The entire idea for the series, a vampire and human in love, is extremely cliché.
15) The fan girls of the series are ridiculous.
16) The movies are just talking heads. They're, if possible, as boring as the books.
17) The movies cast terrible actors/actresses. Kristen Stewart never smiles and always wears the same expression, Robert Pattinson is ugly with all that horrible make up on, Taylor Lautner has spray on abs.
18) When Bella becomes a vampire she's basically invincible with her super shield. There's no real battle or challenge.
19) It approves of pedophilia.
20) There's a Disney ending. Everyone's happy, no one's suffering, and everything works out for everyone. (Both Jacob and Edward get someone, along with all the original couples still being together and alive.) All the bad guys are gone, and good wins at no real cost.