It could just be her way of relating as a teen. I know I was very much "not myself"/who I am now during those years and did not know why or how to be differently. More life experience might change how she relates to you and others; is she this way in school, her events she enjoys? It may just be a negative default she does not mind. The knowing when to turn on the charm before an event she wants seems to indicate she does not connect her "whole" being with her behavior, acts based on how others respond rather than by any personal code. I would throw some personal responsibility in there, ask her to get a job to help afford some of her activities or give her tasks to do around the house for everyone's benefit/support, etc.