I just watched the Nanny Diaries, and I thought it was very to the point.
My very first Nanny job was exactly like what she experienced, times ten. Except for the husband hitting on the nanny part.

Nannies, in those types of families, are not simply the help, they have been degraded to the part of a slave with no life of their own.
From having my days off cut short, to having the kid moved next to my room so that if she woke up she would go to me instead of her parents during the night, my days were taken by the job of parenting 24/7.
The mom actually scheduled time to spend with her daughter, letting me know in the morning that she was going to take her from 2 to 3pm and that that I should be there to take her right away when they were done.
She didn't understand her child, getting mad at seeing her read all the time, when that was her passion.
Both the mother and her husband probably put their own child to bed three times during the summer. I was the one to say good night and I love you every single night.
Within 3 months, the little girl deliberately called me mom. She was eight, she knew what she was doing. She called her mom by her first name.

I felt the same ambivalence when I wanted to quit. Leaving the little girl I had befriended and come to love was just too hard, and I didn't feel like I could do that to her. Just like in the movie she had asked me not to leave her ever. Just like in the movie, a confrontation with my boss forced me to quit and leave at lightning speed.
The way I left in the movie might have been even worse. I told what I really thought of her right to my boss's face before I left, because... like in the movie, she wouldn't pay me my last week's wages.
The kid was right there, although the cook (yes, they also had a full time cook) was trying to keep her occupied, and heard everything that I had to say.
She was precocious for her age and I felt that she needed to know what was going on anyways. Before she thought that her nannies all had to leave for family or life reasons. I felt she deserved to know that we weren't leaving because she wasn't worthy enough, but because her mother was driving people away.
As I left, she was screaming for me, holding the door by both hands so hard that the cook was able to lift her parallel to the floor and still she wouldn't let go.
Her face haunted me for a really long time, and I felt like going back to see her many times in order to let her know I still loved her.

Unlike the movie her mom did not change. After all we always need a fairy tale ended to our movies. In real life, 10 dozen Nannies could tell these women how much they are hurting their children and they still wouldn't care.

Unlike the movie, the pretty Harvard boy did not fall for me, quite the opposite, while I was working for them I got called a peasant by one of those spoiled rich young men. Most of them simply ignored me in the most obnoxious fashion ever.

The money was amazing, but ever since then I work with families that I see are involved in their children's lives, families that still have values, and still love their children. I only am there to help, I am not their to raise their children from scratch.

I was thinking in the past few months how I could work for a rich family like that for the summer. Seeing this movie just reminded me of how emotionally taxing a job like that is. Never again.