In one scene Ben Willis can be seen holding a photo of him and Suzy with a Quality control/Advice label. Looking carefully at the label one can read the following text: 'Blurred out memories. Camera shake - lost steady girlfriend. Focusing error - should have thought of her. Subject too close for comfort - allow 6 weeks to feel better. Plenty more fish in the sea. LIFE WITHOUT HER'
The single shot of Ben falling from the payphone into bed was done in camera and a whole day to film out of the 25 day shooting schedule.
The feature includes the 18 minute Oscar-nominated short film of the same title (Cashback (2004)) within its running time.
In one shot, Ben clicks his fingers to start up time, it then cuts to Ben opening the door to his friend. Between those two shots is a two year gap as the short was filmed two years previously to the feature.
There was some controversy about the scene where the woman walks past the little boy fully nude on the stairs and then opens the door naked when he knocks on her bedroom door, but the actress was never actually nude onset in front of the kid, the scenes were just edited to seem like she was. They show her bare legs as she walks past him on the stairs but it's the only time you see her with him in the same shot. The actress was dressed for that shot. Then the kid was taken off set and she was filmed nude walking up the stairs. Same with the scene where he takes her underwear to her room. They're shown in separate shots because they were filmed at different times.