Why is the chair moving?

So I told you already that I can stand up on my own. Well, here is proof!
This is the best chair in the house, especially when father is eating. I like standing up here, except for some reason the chair wants to move away all the time. And what is this big table above my head?
Also, today at lunch Mierlle came to visit and fed me (for those who don't know, Mierlle is Jennifers' daughter and she is 5 year old, and it is a phillipino name - extra credit if you know what it means!)