Continuity mistake: When Ray and Claude first enter the diner, there is nothing on the door. Later in the scene, the woman asks them if they can read so well how come they missed the sign on the door that says "No Coloreds Allowed"? The sign wasn't there when they first came in and it's not there when they leave.
Continuity mistake: When Claude and Ray have just loaded the truck with the booze, Ray hears music and is trying to convince Claude to go to the club. Ray is holding up money and from the back it is folded up but very messy and the roll is thick, From the front it is folded very neat and the roll is thin.