Temper tantrums are starting

Lately we noticed that Baby Xin is starting to throw temper tantrums.  At this early stage, it seems very cute to us.  For example, yesterday, she wanted to play with the baby powder container that has the powder puff inside.  She took out the puff and held in her hand.  I wanted to keep the thing back, so I took it from her hand, put it back inside the container and closed the lid.  She quickly grabbed the container and tried to open the lid to get the powder puff back.  When she couldn't open the lid, she simply lay down on the floor, faced down, and cried inconsolably. When we opened the lid for her, she immediately stopped crying.
Ok, so we are evil parents.  We experimented with this twice, and each time the same reaction.  Lying on the floor face-down, and crying like the sky has fallen.  J and I laughed, and then opened the lid for her.
Hmmm, we find it cute now, but we are thinking when she becomes a toddler in her terrible twos, we may be seeing a lot more of that lying-on-the-floor tantrums.