The document discusses genres and how they develop through repetition and recognition of conventions. Audiences come to expect certain conventions within different genres, like horror conventions in Halloween or teen conventions in Mean Girls. Genres are successful because audiences find familiarity comforting but producers also need to innovate somewhat to avoid boredom. Genres thus rely on a balance of repeating familiar conventions while also adding new elements or twists. This allows audiences to enjoy what they know while still being surprised.