When Karen first enters the ladies' room, she removes a tube of mascara from her purse and places it on the countertop. After the waitress Betsy leaves, Karen turns back to the mirror, but the mascara is no longer on the countertop.
When Melonie re-enters the room with the projector, it is not running... twice.
When Michael asks Andrew to help him use the grandfather clock to break down the door - he has already moved it with one hand from the wall and it is obviously a very light prop.
When asking his daughter for the ceiling fan's code, he asks for them in a counter clockwise form. She reads them out in the opposite direction.
After stopping the fan in the attic, Michael tells Karen to read him the numbers "counterclockwise." Karen proceeds to read the numbers off clockwise; 7-3-8-2.