When Grace gets two bottles of beer for her and Mark, she sits down on the sofa with both bottles in her hands, yet in the very next shot one of the bottles has jumped into Mark's hand.
When Grace gets two bottles of beer out for her and Mark she removes the lids on the beer bottles. In the next shot the lids are back on both bottles.
When Grace is in the toy shop, and is hiding in the ball pit from Mark, the color of the balls around her changes.
Grace's boyfriend has six toes but in close-up shots of when he takes off both socks you can clearly see only five toes on each foot, when they are specifically trying to hide one foot.