Harper is purposely concealing her sexuality, Abby is forced into the unfair position of pretending she's someone she's not, and the whole Caldwell family is bound by pursuit of perfection — except Jane. While still striving to be loved by her parents and sisters, Jane acts how she wants to act. She hugs Abby under the assumption that Abby is an orphan because she's an empathetic human being. She tells everyone who will listen about the fantasy book she's writing, because building the world is really exciting for her.
Perhaps because her parents gave up on her when she went through a biting phase as a child (totally normal, by the way), she was given the opportunity to grow into a person she really likes — and that's awesome.