Just remember, developmentally she has no perspective. So when she says "I hate you, you are the meanest mommy in the world" or whatever, at that moment, likely she really is feeling it. Though, at 3 is when they do start to develop some abilities for manipulation too. Just remember it is not malicious - she is trying to make sense of her world and how she can exert control over it.
To Trenell, MizKerri and geeky:
I pray none of you ever has to live in a communist state.
Geeky is my hero. She's the true badass. The badass who doesn't even need to be a badass. There aren't enough O's in cool to describe her.