In many traditional cultures, fathers and mothers would pray for a boy who would be able to help in the field. In these cultures, the value of daughter was not understood. A father has a special relationship with his daughter as she will judge all men by his standard. A mother's task is to show her daughter the complex task of growing into a woman. We no longer live in an agricultural society and woman are free to accomplish intellectually and occupationally what they couldn't in the past. A daughter may one day play the role of mother and wife. Raising a daughter is an infinite gift.
Mother and daughter relationships are complex because the daughter looks to her mother as a role model of what a woman is. As she grows up and sees other woman who live their lives differently, she chooses between imitating her mother or other significant influences in her life. As an adolescent she may come to look down on her mother and think that other woman are much better. Of course she is not a fully grown woman so she does not understand the challenges and choices that her mother faces. It is only when she herself becomes a woman that she can fully appreciate her mother.
Having a sister in your life can either be a wonderful or terrible experience, depending on your relationship. If you have an older sister and you are a girl, she can often show you how to navigate the way through some of the more difficult areas of growing up. This is also true if you are a boy. Your older sister can help explain to you how to interact with the opposite sex. Younger sisters are a joy as well. They often worship their older siblings and it can be a nice experience to be admired. Relationships with sisters, like any relationship depend on the people involved.
Saying thank you can be a difficult thing to do. Doing so means admitting that you are in another's debt. I am admitting that another individual did something for me. I am not all powerful, I need the help of others to survive. The reality is that the human race is interdependent. We cannot live life alone. We are constantly relying on each other for all kinds of resources, both physical and emotional. When I say thank you I am acknowledging that I have received something from another human being.