Continuity mistake: In Season 5 Episode 18 "George Helps Ernie See the Cellu-Light" Angie is eating chocolate cake before Ernie comes over. Carmen is talking to Angie, and Angie has two big pieces of cake by her fork, but in the next shot, the two pieces are completely gone, and we don't see her put it in her mouth.
Plot hole: In the very last episode of the show, "George Decides To Sta-Local Where It's Familiar", Angie mentions that they conceived their "kids" there, referring to both Carmen and Max. However, the season four episode "George Takes a Stroll Down Memory Pain" showed flashbacks where Angie and George were living with Benny, and Angie was far along in her pregnancy with Carmen. Only Max could have been conceived in the house that they are currently living in. I want to add that in the episode 'Valentine Massacre', George says"What about the first time we made love. What were the odds in Vegas!?!"
Continuity mistake: In some of the beginning episodes, whenever George is at work, you can notice that it was originally called "Powers and Sons Aviation", but later in the show it calls them "Powers Bros. Aviation." We even see the Powers Bros. in a few episodes, and in one episode Mel Powers' son smashes up the factory.