Continuity mistake: Season 4, Episode 19, "My Name Is Alias": While Darnell's farther has his back to Earl, Earl tries to jump him; Darnell's father hits Earl, and Earl falls to the floor. When Earl gets up, take notice that Earl has a cut on his lower lip; the cut goes from a vague light red to a dark red in several quick shots.
Continuity mistake: Season: 4, Episode: 17, "Randy's List Item." In the scene where Randy and Arlen are sitting in the bar, and Randy is telling Arlen how to be a better little brother, take notice that the beer bottles on the table increases in number, and the arrangement of the bottles changes too.
Continuity mistake: Near the beginning, when Joy sees the IQ game, the two poles are close together and there is nothing directly beside it. But when she gets close and the camera changes angles the poles are now separated and a small gold toy is sitting beside it. Then when she leans down next to it the poles are still separated, but the toy is gone.
Continuity mistake: Episode 10 of Season 4 ("Earl and Joy's Anniversary") has Earl yelling "Fire!" from inside the Crabshack's restroom. As he does, a woman with dark brown hair and wearing a blue plaid shirt gets up from her table to evacuate the restaurant. A long shot outside the restroom of Earl yelling "Fire!" has the same woman getting up and leaving again.
Continuity mistake: Season 4, Ep 2 - "Monkeys Take A Bath": When Earl's mother is in the bathroom stall we see she has a tiny bit of toilet paper on the roll next to her. As Joy puts her head underneath the stall the amount of toilet paper is now much longer than before. It goes from half a square of paper to about 2-3 squares of paper.