In the episode when everyone thinks Grandpa is going to die because of the "family curse", Grandpa realizes he won't die and he and Arnold go out for ice cream at... wait a minute! It's past midnight and they are going out for ice cream.

Also, in the dining room had only one door and it was on the right and the boarders were going left to leave the room. But they would be walking into a wall if they went that way!