This is a beautifully acted, well written film. I believe some people who disliked it were expecting a comedy and therefore disappointed. It seems more a psychological drama about a woman who is so sleep deprived, stressed out and unsupported by her spouse, she actually creates a nanny (her younger self) to help her cope. I liked it, much as I liked the Sixth Sense. Somewhere along the line, you have to see the clues. Bruce Willis character is dead and Tully isn't real. Tully, we find out later in the film, is Marlo's maiden name, when she arrives she is much younger than expected, they hit it off like best pals despite the age difference, Marlo said she didn't want a stranger in the house at night and yet she trusts this young girl immediately, her husband doesn't even go downstairs to meet the nanny, when the car crashes into the water Marlo is alone in the car....there are endless clues that Tully doesn't exist.
I hope the fine acting is remembered at Oscar time.