First of all, we have Zhao Yanzi, she is still a young girl and has a rather bad temper, and yes, she is a brat. I won't deny it, she is a brat. BUT her character is perfectly in line with her setting, more perfect than any other character actually. Actually, the ones responsible for her behavior are her parents, the reason being that they spoiled her rotten. She gets almost always what she wants from them and if not, at least until some time ago, she would get it from Zhao Kuo. And although her parents may not give it to her directly, they still won't prevent it. And that would be their responsibility as her parents.