All the characters annoyed me and the fact that she introduced characters and never really developed them. It really annoyed me. The Kill Club, her aunt, Angel of Death, her Dad. Especially how they didn't develop her aunt's character. You think with the way she was described as a real go getter - Gillian would have developed her character a little bit better and made her more a part of the story. Helped Libby grow or solve the mystery and find out that she is a great aunt, but she is just MIA. Especially when Libby left a message for her on her answering machine your expecting some sort of character introduction/development, but nothing. Ben was just pathetic and basically did nothing but allow events to happen around him. Diondra yet again tries to take the life of another sister and he sits idly by protecting who? His daughter, so she turns out to be a killer like her mother??!?! WTF? I mean wouldn't you rather turn the mother of your child in and allow the one relative you have and love raise her? Your sister (I mean not when she was born, but between his Aunt and Libby, it was possible and poor Libby might have been an actual fully functioning adult (which she became at the end, but it would have saved everyone more grief)). Also, the fact that Libby went to confront/meet Diondra alone and wasn't the slightest bit creeped out by her place or the fact that she has a niece that was seven years younger than her? It seemed as if Libby accepted that a little too fast, even for her.
The angel of death was also another one of those characters. It is just touched upon at the Kill club and then here he comes to tie up all the loose ends in a nice little bow. She didn't do a good job foreshadowing that character in my opinion. While reading this you can tell that she is developing and working her characters out and hasn't quite got it figured out like gone girl.
I don't think I'll be reading her first novel after this one. I may still be interested in any future novels she may write, but I'm ok not reading her earlier work. Looking forward to reading what others have to say about the book!