My DD can be like this. She has ADHD and is particularly volatile when she is not medicated, or when it is wearing off. I try not to engage with her. For instance with the panda, I probably would have calmly (albeit irritably) told her that I'm not going to help her if she's going to yell at me. Dh tends to get in ridiculous arguments w/ her, like they are both 7 years old ("I said X" "no you didn't!" Yes I did!" "No you didn't!", you get the idea), which just makes things worse, esp. as they get more and more off-topic.
Strangely, she is not like this at school...I think she knows that people would dislike her. Teachers get up in arms about my other kid and his mild grumbling, like he must be pathological because of it, but he is a piece of cake compared to DD at home.
