Anne feels closest to her father Otto Frank in Act One, because she fights with her mother and everyone thinks her sister is perfect.

When Anne and her family and the Van Daans come to the Secret Annex, they have a little trouble getting along.  The Van Daans have a son, Peter, who is older than Anne.  He and Anne fight almost immediately.  Anne and her mother also have constant arguments.  Anne feel like the only refuge is her father.

Anne’s closeness to her father hurts her mother.  Margot, Anne’s older sister, tries to explain to her mother that Anne is not trying to be hurtful when she wants to see her father instead of her mother.

 It’s a phase . . . You heard Father . . . Most girls go through it . . . they turn to their fathers at this age . . . they give all their love to their fathers.  (Act 1, Scene 4)

Anne herself feels bad about things she says to her mother, but she also gets very frustrated by how her mother, Mr. Van Daan, and Peter treat her.  Anne feels that she gets no respect from any of them.

Being locked in close quarters with her family and the Van Daans is torture for Anne.  She is a young and boisterous, sociable girl.  In the hiding place she has to be quiet most of the day, and never gets any privacy or alone time.  She is surrounded by nagging adults telling her how to be and what to do.  For Anne, only her father and her diary are really there for her in Act one.  Ironically, in Act 2 she will become much closer to Peter.