Continuity: While they're having dinner, Johnston spears several carrots on his fork, nudging one off the edge of the plate and onto the table. In the next shot, it's gone.
Errors made by characters (possibly deliberate errors by the filmmakers): When the covers of Carmen's books are shown, one misspells "Enlightenment" as "Enligtenment."
Continuity: When Don speaks with the receptionist at Dr Markowski's office, the angle of the laptop relative to the table changes repeatedly between shots.
Continuity: The blue rental car that Murray drives to the farmhouse has different style wheels than the car that Murray wakes up in after being beat up.
Continuity: In all of the driving scenes, the windshield sticker is always from New Jersey - even though he's flying between locations.
Continuity: Around the 1hr mark of the film, after Don gets off the plane and is driving over the bridge, his sunglasses appear on, then the camera angle changes and the sunglasses are off, then on again at the next camera angle change, with no indication that he had taken them off
Errors in geography: As can be evidenced by the symbols on the airport signs (the letters A, B, and C, individually, are in the center of rounded triangles, designating sections of the airport) Newark Airport (NJ) was used for each of the airport scenes, although Murray's character was supposedly going to many different places in the US.
Continuity: (At 17:00) During the scene where Winston goes back with the pink letter to Don's home, after he turns down the volume he sits down we can see the lampshade on the side table changing position to the next scene when the pink letter is on the table in front of Don's couch. This can be seen on the profile shots of Don and the lampshade on the background relative to unchanged camera angles.