Continuity mistake: Meg comes in the kitchen and Peter pulls out her chair for her. Next shot of Meg shows a plate of food appear out of nowhere. Peter, Lois and Chris had a plate in front of them and there was no plate in front of Meg at any time. There was no other food in sight on the counter or stove either.
Continuity mistake: In this episode, Lois is shown to have dated Naomi during college. In the episode "Meet the Quagmires", it was established that Lois and Peter were already dating when Lois was eighteen. She accepted Peter's marriage proposal at that age. She would have been engaged and possibly married during college.
Factual error: Brian is sitting on the couch smoking weed. Joe knocks on the door and Brian just waves the smoke from the air. Joe is there to give Brian a drug test and says nothing about smelling weed in the air. There's no possible way he didn't smell it! You can't just wave your hand and get rid of the smell.