The movie is horribly overdramatic, with no actual basis for a relationship, no emotional development, no getting to know each other stage. They're just suddenly in love. That's not how it goes. The best characters in the movie are Charlie and the biology teacher with his golden onion.
However, then you get to the book. Reading the book again, I was reminded of how sarky Bella can be and how actually funny Edward can be. I was reminded of them eating lunch together, of them talking, Edward explaining Carlisle's story, explaining Rosalie's behaviour better, them actually getting to know each other before they decided they were in love. That is far more realistic to me. And let's not forget that there are actually background characters in the book - Jess, Mike, Eric, Angela, all have much better, more individual characters than they do in the movie.
I also think that the book develops the plot better. Initially it's a normal thing like a girl moving to a town she hates and settling in. Then it becomes strange with a kid who's not quite human. And then he and his entire family are vampires and regardless of this, she loves him. And then, holy crap, there's a hunter out for her blood. But the story progresses well enough that you don't realise how big the difference is until you compare the beginning and the end.
I have been through several stages of my opinion of Twilight. I started as a mindless fan. That haze then faded, and I turned to the other extreme of mindless hatred, helped along by the other fandoms I was in. However, having now had the storm against Twilight die down and having given several years in between, going back to it now with a fresh mind has opened my head to more objective views. While Twilight is by no means anywhere near the best book I have read, it is also nowhere close to the worst.
I hope that others, as they get older (I know I was very young), will also be able to give every book series the open-minded chance it deserves. Opinion past that is entirely your own.