I am the mother of 3 children, 18, 11 and 2 1/2, will be 3 in April. My first two had their moods, but nothing like my 3rd. He acts much like your daughter does. Sweet, loving and well behaved and suddenly becomes what my husband lovingly refers to as "demon spawn". We have initiated a "tantrum spot". Its much like time out. Initially we had a very hard time keeping him there, but we would just put him back and tell him that when he was done, he could get up. He still has his mood swings, but they are now fewer and farther between and are considerably shorter now that he has the spot. I really believe that it is a way of trying to gain control, which is what toddlers do. They try to gain control of walking, talking, playing, their environment, even the household. It is our job as parents to set reasonable limits and then to enforce them. (I know, this is where youre thinking - easy for you to say) Its definitely not easy, but it gets a little bit easier every day. We actually were able to take my son to a restaurant last night and not have any problems!!! It was a first for us. So, good luck and keep trying.