Dakota Fanning's character is named Lucy Diamond from The Beatles song "Lucy in the Sky with Diamonds." Michelle Pfeiffer's character's name is Rita Harrison, from the song "Lovely Rita," and the last name of Beatles member George Harrison. Sam, Lucy, and Sam's friends walking across the street with the balloons is a tribute to the case cover of "Abbey Road." Sean Penn wanted the soundtrack to be all Beatles music but was unable to get the rights, so he asked various artists to cover the Beatles songs he wanted to use. And in order for the re-recorded music to fit into the movie, each of the artists had to use the same tempo as the original Beatles songs.
Many lines or actions by Sean Penn's character, Sam, are improvised; for example, the end of the scene at the new restaurant where Sam shouts, "Ask Big Bob!" or the dog scene. The producers liked many of these improvised scenes much better than the original book.
Michelle Pfeiffer took on the female lead because she was friends with the film's writer and director, Jessie Nelson, who had co-written the screenplay to the actress' earlier film, The Story of Us (1999), and because she wanted the chance to work with Sean Penn.
There was originally to be a line where Brad (Brad Silverman) asks Rita (Michelle Pfeiffer), "Are you wearing a Wonder Bra? Because you look wonderful today..." but Silverman thought the line was offensive to David E. Kelley (Pfeiffer's husband) and refused to say it.
The trivia items below may give away important plot points.
Meanwhile, the 2 new people Comes In One Is Male and The Other Is Female. A Male person is 17 years old and the female person is 18 Years old but they have a relationship. On the scene when Sam tries to get Lucy back, Jay And Janice Settle Their Own Score on their Foster parents And on the thirteenth scene, Jay Terrorizes His Enemy Lucy Dawson! So at the end Jay and Janice Burns Down the Foster home and they ended up getting Arrested.
The New Character Comes In One Is Male and The Other Is Female, A Male Person Name is Alex And A Female Person Names is Jennifer And They Both Have a relationship, They Were Nice At the beginning but they turn Insane at the end but Meanwhile, The Persons Settle Their Own Scores At Their Foster Parents And At The Scene when Sam tries to get Lucy back, They Brutally Kill Lucy's Foster Parents By Stabbing Them To Death Except for Sam And Lucy And Jake Said "All Is Over" And Janice Said "Clearly We Killed All the Foster Parents, Now We Must Burn This Place Down" At The End, They Set The Foster Home Burned To the Ground And Jake And Janice Got Arrested And Sentenced For A Year And 22 Weeks But In The Sequel They Will Return and By the Help Of Jakes Friend!! So That's Why Jake And Janice Are The Main Antagonists In This Film??! But The Names Are Real But They Aren't Revealed!!