Continuity mistake: In the pilot episode, during the breakfast scene, there are five donuts in the box in front of Roger before his chair breaks. When he takes one from the box, there are eight. When Francine takes his donut away, there are five in the box again.
Continuity mistake: Steve, Hayley and Francine all stand next to the door when Bullock arrives. They are all standing right next to the door in the shot where Stan adjusts their clothes. But they have magically moved a foot away from the door in the following shot where Stan opens the door.
Continuity mistake: When the bus driver finds Roger, the Dignity Towers Retirement Home bus is only a few feet away from them. But in the shot where Roger says "How do I get home? How do I get home?", there was no sign of any bus for many many meters. As if the bus just appeared out of nowhere.
Continuity mistake: When Francine brings lemonade on a tray for Steve and his friends, she assumes Snot is drowning. Francine then drops the tray and it lands on the ground before jumping in the pool after him. The tray disappears when she emerges from the pool with Snot.