Earl and Joy's Anniversary - S4-E10
Continuity mistake: Earl yells "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.
Answer: The premise of the show is he atones for mistakes he did in the past. Winning a car for Joy probably atones for something he did wrong regarding her in the past.
Rob245