Mark Ruffalo's first scene was the "Thriller" dance sequence. He was terrified of doing the scene, but Jennifer Garner's enthusiasm was "very infectious". Andy Serkis had to rehearse the scene separately from everybody else, because he was in London at the time.
Jennifer Garner was very happy with the studio's choice of Christa B. Allen to play the young Jenna Rink. She felt Allen really embodied her at that age, and later got the producers of Minhas Adoráveis Ex-Namoradas (2009) to cast Allen in a similar role.
When 13-year-old Jenna Rink goes into the closet for "seven minutes of heaven", you can see actual photos of Jennifer Garner as a child on the back of the door.
As Jenna Rink softens, the production team adjusted her wardrobe accordingly, for example, wearing warmer colors. As Lucy Wyman (Judy Greer) becomes ruthless, her fashion sense goes the same way.
Jennifer Garner improvised a great deal of Jenna Rink's child-like observations. For example, when Alex Carlson (Sam Ball) wants to play sex games with Jenna, she suggests Battleship.