Further adjustments were made to finesse the script once the cast was finalized. Marshall was constantly conceiving new ways to make the film funnier, as Disney had challenged him to incorporate humor into the G-rated film. Marshall's approach to the film's humor was reminiscent of his television contributions to shows such as "Happy Days" and "The Odd Couple", the original scripts for which he revisited to remind himself how to approach family-oriented comedies. Matarazzo described the set as a collaborative environment, recalling that Marshall encouraged a family-like atmosphere abiding by his motto "Life is more important than show business." Marshall would sometimes hold parades for the entire crew, particularly when it was a cast or crew members' birthday. The director celebrated his own birthday while filming, during which Houston herself serenaded him with a rendition of "Happy Birthday". The character of Mia's grandmother, nicknamed "Grandmere" in the novel, is depicted as considerably kinder in the film. Disney's decision to have Mia's father be deceased in the film is among the most significant deviations from its source material, in which he is both alive and has an integral role. The producers decided to kill off Mia's father in favor of expanding her grandmother's role, which they had been considering offering to Andrews from the beginning. Upon learning that Disney was interested in casting a "big name" actress such as Andrews in the role, Cabot approved that Mia's father be eliminated, much of whose dialogue was re-written for Mia's grandmother. Marshall wrote Hathaway's childhood struggles with speaking while wearing a retainer into the film; the actress filmed a scene wearing the same retainer she had worn as a child. Elizondo and Andrews campaigned for a romantic relationship between their characters, an idea that originated during a table reading in which the actors uttered "you're cute" to each other. The actors improvised their dance sequence. Elizondo credits this with evolving his character into more than simply "a guy who drove a limo".