How can the reader tell that Abby and Hadley are childish and badly behaved?

Abby and Hadley act like they are friends, but Abby likes to steal Hadley's boyfriends. The girls have a food fight at the studio, and Hadley refuses to be interviewed, even though many people are depending on her for the show. Hadley also refuses to be in the movie, even though she has already agreed to do it.