In this episode, Tim's old shop teacher comes and visits him at his home. Tim grunts, and Art, his teacher, asks him what that noise was. He said that it was a grunt, and that he figured it out in college. However, in the episode "Ex Marks the Spot", Tim's old girlfriend said that he used to grunt when he went by hardware stores. This doesn't make sense because Tim went out with Stacy in high school.