From the way you describe your daughter in your post, it sounds like you have a lot of negative feelings towards her (she's lazy, whines, complains, ungrateful, etc) and it sounds like she can feel all of this from you. You also mentioned she believes you love her brother more. That can be incredibly damaging to a child's self-esteem. Instead of just punishing her, I would recommend really sitting down and talking with her. Try to understand things from her perspective and compliment her positive qualities. If she feels loved and feels you recognize her good qualities, her self-esteem will increase and she will be more motivated to get along with you. Sometimes it's really important to listen and understand what is going on for the child. Going through life truly believing you are the unloved sibling can be one of the most painful things in the world, and showing her this isn't the case would make a huge difference in her life. While you can punish her behavior, I would really try to avoid saying negative things about her qualities (even to yourself)-- try not to call her lazy, etc. try to life her up instead of criticize her. If you improve your relationship with her, her behavior will improve, too. Most children just want proof they are loved and understood.