Continuity mistake: In the opening scene, Andy is seen eating a bagel, then the shot changes and she has no bagel, but when she goes down the stairs into the subway the bagel is back in her hand.
Continuity mistake: In the scene where Andy is sitting in the restaurant with her father, you see her father taking off his glasses. In the next shot you see the father from the back, taking off his glasses again.
Continuity mistake: When Andy throws her sidekick into the fountain, she is holding it in one hand. The reverse shot of the face of the sidekick shows her holding it with both hands.
Continuity mistake: When Miranda puts her coat and bag on Emily's desk in the scene where Andy has to tell Emily she isn't going to Paris, the bag is standing up. The next shot shows the bag flat on the desk and turned.
Continuity mistake: In the restaurant where Andy is giving her friends presents, she hands her friend a little clear case of Clinique products, but when she's putting them in her friend's hand, she is also holding a blue box when she wasn't before.
Continuity mistake: When Andy first meets Christian at the party, her hair changes throughout the scene. First one side is in front of her ear, then it's tucked behind it, then it's in front again.
Chosen answer: Miranda was going to be replaced by Jaqueline and forced to retire. Miranda worked a deal to give Nigel's new job to Jaqueline instead. Since Jaqueline now has a job she wants, there is no one eager or qualified to replace Miranda. Miranda keeps her job. Nigel doesn't get a new job and must remain with Miranda. Miranda gets what she wants, Jaqueline gets what she wants, Nigel gets screwed, but maintains the (most likely futile) hope that Miranda will pay him back by some other means in due course.
Myridon