In the scene where Ian confronts Rob at the record store, Jack Black`s character is wearing A Clockwork Orange tee shirt. In one of the fantasies Rob has where he, Dick, and Barry throw Ian to the ground and beat him, this mirrors a scene from A Clockwork Orange where the Alex, Pete, Georgie, and Dim beat a homeless man. Barry even uses a belt in the act the way Dim used a chain.
In the movie Rob says one of the books he's read is love in the time of cholera which was the same book cusack's character looks for in his movie serendipity
When Rob refers to John Dillinger being shot by the FBI he claims that it was Dillinger's own girlfriend that had sold him out to the FBI, but this wasn't the case. The FBI were informed by Ana Cumpanas, (the landlady of the hotel that was harboring him) after they had threatened to deport her.
Rob mentions the song "Landslide" while holding up the
self-titled Fleetwood Mac album, which it appears on. The cover is similar to the cover for "Rumours", which confused at least one viewer.
During one of the phone conversations between Rob and Laura, Laura is shown in fairly tight close up. She is holding a "slimline" phone handset and at the extreme bottom edge of the frame you can see that although there is a phone cord socket on the phone, the cord is not attached. This is visible several times during the conversation.
Rob: She didn't make me miserable, or anxious, or ill at ease. You know, it sounds boring, but it wasn't. It wasn't spectacular either. It was just good. But really good.