Why is Anne upset at the treatment she receives from the Van Daans?

Anne is only thirteen years old when she begins to write in her diary. She is full of curiosity and hope, and she yearns for true friendship. She seems to be very intuitive for a girl her age, and she places a lot of emphasis on her relationships with those around her in her private writings.
Anne and her family are trapped in hiding with the Van Pels, whom Anne has decided to call the Van Daan family. The patriarch of the Van Daan family, Hermann, worked with Anne's father before they had to go into hiding, so the two families had a casual acquaintance before they were forced into close quarters with one another.
Mr. and Mrs. Van Daan seem to look down their noses at Anne. They consider her childish and place little value on her beliefs or opinions of things.
Peter Van Daan grows to be Anne's close friend. He is the first boy she ever kisses, and they seem to hold each other in mutual regard, even though, at first, Anne and her sister Margot spend many hours making fun of the young man.
Anne is upset by the elder Van Daan's treatment of her because they seem condescending and harsh. She is hurt by their dismissal of her and feels betrayed that Peter does not make more of an effort to show her importance in his life.