Response to Julia's "Necessary Revenge"

Overall, I was entertained by this story. The character development at the beginning was excellent, and I loved the attention to small details like when Sarah couldn't quite remember her nanny's name. This gave a lot of realistic personality to Sarah right off the bat. I feel, though, the same could be done with Emily. Although we get a little bit of her background and see a vague picture of the relationship with her brother, I'm left wondering what it is, exactly, that drives her, and what could be her ruin.
There are a few issues in the story I'm a little confused about. Right at the beginning of the story, the narrator labels herself as "Daddy's Girl." Does this imply that she is overtly loyal to her father, or is it just indicating that she has access to all his money? Her sexual nature leads me to believe she's not so much of a daddy's girl, but more a sycophant.
Money is a key element in this story. It seems the livelihoods of the women revolve around fancy drinks and expensive, revealing outfits.
I also want to know more about her best friend Emily. What kinds of things did they do together when they were younger? Have they changed at all? Why did they become friends in the first place? Have they gotten in any vicious arguments? Answers to these questions will solidify the reader's relationship with the relationship between Sarah and Emily.
I felt I was understanding and connecting to the characters for the first part of the story, but by the time the women are at home and Emily blows up about the war and having friends like Sarah, I felt strangely disconnected. I felt, for some reason, that these were not the characters I had been introduced to earlier. I understand (though vaguely) that Emily's relationship with the war has done something to her perception of the world, but even when she's explaining how she feels to Sarah, I'm left with a lot of questions. I suppose I don't entirely get why Emily's so gung-ho on revenge and why she's so ashamed of her brother.
I don't think the story should end where it does. I feel there are a lot of things unresolved, and when Emily just walks away at the end, turning her back on her best friend and her life and everything, well, it's just not enough for me.
The nice part of me wanting to know more is that I want to keep reading. Julia has hooked me on the characters, but now I'm at a point where I'm invested, but not satisfied. I think this could be a nice starting chapter of a longer novel.