Continuity mistake: When Monica and Frank are driving in the car with Liam, the Crawford Power Plant can be seen just behind the car. At this point, they have crossed the Stevenson Expressway and they are heading south down Pulaski. However, in the scene where they stop the car and argue, as Monica drives away, the Crawford Power Plant can be seen on the left, right ahead of them.
Continuity mistake: When Debbie sits down on the couch with Carl and Liam, Liam is sitting on Carl's lap with Carl's left arm around him. When the camera angle changes, Liam is sitting next to Carl, and Carl's hands are in his lap. When the angle changes again, Carl's arm is once again around Liam. It changes back one more time to Liam sitting next to him before Carl gets up to answer the door.
Continuity mistake: After Fiona's return back home from the club where she's worked as a waitress, the blackish strips on her cheeks turn from partially rubbed off (justified by her wiping the tears) to perfectly fine a moment later, then change several more times during her discussion with Lip.
Visible crew/equipment: When Monica stops the car, as Frank is getting out, you can see two cameramen in the reflection of the window. Also, a train is passing by but during the shot where Frank gets angry and makes a mean face at the camera, cars are passing along as if there is no train at all.
Continuity mistake: During Frank's discussion with the candidate for mayor, there's a bus leaving the stop, it's not the same vehicle. In the first shot, it's 1717, with no advertisement or line number on the rear, while in the second it's 1691 with an ad above the licence plate and the number 82 on the display.