This post is about both the book and movie.

Working for a tough perfectionist boss in one thing. Working for a boss who is unaware slavery has been abolished more than a century ago, that gives vague orders and keeps changing them, who abuses the employees, who never has any kind word to say but chides nonstop... that unbearable.

If Andy liked her job, maybe it was reasonable for her to stay and somehow put up with Miranda's nonstop abusing. But she hated her job, every second of it, the long hours and constant stress, being isolated from her friends... she couldn't even go to a dentist to treat her aching tooth!

Instead of showing some backbone, telling Miranda firmly that she was not her goddamned slave and then quitting, she did exactly the opposite - obtaining Harry Potter books for Miranda's daughters. What did Andy prove by that? That she was a doormat. An abject slave. Didn't she have some self-esteem?!

IMO Andy did better in the book: when her majesty gave her an equally outrageous order (to renew her daughters' passports a very few hours before the flight, when she was out of USA) she finally snapped and did what she should have done a long ago: told Miranda "**** you" in public and walked away, losing her job but regaining her old self.

As for replacing Emily: yes, Emily was awful to Andy, and deserved some payback. But that was not the point. The point was whether Andy was willing to step on others. That was in contrast to her personality. No wonder she felt so bad afterwards. Moreover, being threatened by Miranda... why didn't she say "I want to be promoted, but not that way. And I will never comply to threats!"? The worst thing Miranda could do was fire her, and she hated her job anyway. By accepting, she made herself Miranda's puppet.