In a bar, as Nancy drunkenly explains her mess of a life to Chu Chu, she angrily swipes her glass off the table she sits. The glass can be heard to tumble and break on the floor. Towards the end of her drunken slurred words with Chu Chu, she lifts her head and pours the rest of her wine from the bottle into her glass that has reappeared and gulps.
The mailman delivers a single letter to the Ames residence and tosses it through the odd, open mailbox, and it gets hung up in the wire fence. But when Mrs. Ames goes to the mailbox, a rolled-up second piece of mail has appeared.
When Mrs. Ames is making the bed, she has folded and smoothed the blanket. When Ames enters the room, she pulls the bed cover up over the blanket, which is not tucked in.
In the bar as Nancy is drunkenly explaining her mess of a life and swipes her glass off the table that crashes to the floor, no one in the bar turns their head to acknowledge the noise. Surely, someone would have noticed.
Not a Continuity Goof and probably not even a Goof - in some bars, breaking glassware is very common, and though people notice, they don't turn and gawk, because they feel everyone should mind their own business.