I find her annoyingly pessimistic.. She's totally ungrateful for anything anyone ever does for her.
She's bored and annoyed about her GRADUATION, her BIRTHDAY, the huge PARTIES that Alice always tries so hard to set up.
If I was lucky enough to even live NEAR Edward, I would thank God for just that (yes, I'm a fan xD ). She gets to be his soulmate for eternity and she always finds something to complain about.
She's incredibly selfish, and the only time she was ever optomistic was when she got pregnant, which was more serious than anything she'd ever moaned about. I hated that kid, it was hurting Edward so much, but, yet again, it was all about what Bella wanted.
She has good points, too.. Sometimes.. But I know there would be better people for Edward than her.. *points to self* xDDD