Continuity mistake: After Nick becomes a hero, he wears a cast on his right arm. However, when he and Kate go to dinner with Kate's boss, Nick's cast mysteriously disappears for one shot. They are sitting at the table at the beginning of the dinner and Nick picks up a glass with his right hand, with no cast. The next time you see Nick, he has a cast on his right arm again.
Continuity mistake: There is a scene where Kate comes home and her mother is standing right there. Kate starts yelling at her mom. When Kate first comes in the door she puts her purse behind her back on the counter and the purse is leaning on her back. If Kate were to move, the purse would have fallen on the floor. In the next shot, Kate is further away from the counter and the purse is standing straight up as if it was put there like that.