That's been the explanation for Ellie's "undesirable" behavior in recent months. It doesn't happen all the time, but when Ellie goes into her monster-mode it can be plenty scary. And it can really ruin the whole day for both of us! But I've been reading as much as I can recently on the best way to handle my temperamental toddler... because I really want to make things better.
Here's some insight I found at babycenter.com:
Trying to get respectful behavior out of a 2-year-old is like trying to get blood from the proverbial stone. That's due, in part, to the fact that a 2-year-old's language skills are still developing. So when you tell him it's bedtime, he can't say, "Gee, I'm really having fun with my trucks, and I wonder if we could negotiate for five more minutes of playtime?" He's more likely to ignore you, stick out his tongue, or yell, "I hate you!" at the top of his lungs. This doesn't mean he's a lost cause — only that he's very young and still needs years of consistent teaching and practice to learn how to show respect.
I found this helpful because too often I forget just how little Ellie still is. Now that she's not my baby anymore -- well, not my littlest baby -- I find myself expecting a lot from her. Patience, help and respect, just to name a few. But Ellie is still learning, and as they point out in the blurb above, it's my job (and Brian's) to teach her. I get frustrated from having to ask for "please" and "thank you" from Ellie a thousand times each day, just as I get frustrated when she ignores me or collapses into a ball on the floor... but I need to remember that I'm the teacher and she's the student. Losing my temper isn't going to teach her the best way to handle a situation -- even though it happens on occasion. I guess Ellie and I are both working through the terrible-twos right now. I welcome any advice others have out there, otherwise just send some deep breaths and good thoughts our way :)