If Enoch is angry about the fact people leave others behind when they die, Annabel takes it very peacefully. Annabel's philosophy leads her to deal with whatever situation with a smile and a positive attitude. She enjoys every moment, and invites Enoch to do the same, because this is how life should be lived.
Casting was really well done : choosing Mia Wasikowska as Annabel was a good idea. Her angelic face and her cute smile is easing the difficult subject this movie is dealing with. Also her sweet features are calming Enoch and the audience as well.
I know I saw Mia in another movie but I could not find out what it was. Internet gave me the answer this morning : Alice in Wonderland.