Because of Dr. Carlisle Cullen!!!! DUH!!! :) lol As well as Steph Meyer's ingenuity in the story itself :) Not the best to read grammar-wise, but it's something I think should be enjoyed when reading for appreciation/entertainment :)
I'm a fan of twilight because of 5 main thing:
1,I feel I can relate to Bella
2, Edward, Jacob and Emmett are amazing
3,Stephenie bring a new take on Vampires and Werewolves
4, The booka are well written
5, I like the romance of the story