What am I, your dog?

Matthew has somehow discovered the art of the "command", and he seems to get a real kick out of having Sean or I "fetch" things or do things for him. He will throw a ball across the room, and the point to it and say "Dada!", and then wait for Dada to fetch. Or, he'll come over and hand me a puzzle piece, and then run over to his puzzle and point to where the piece goes, and say "Mama!".

When I tell him he can get the ball (or whatever) himself, as in, "You can do it," he insists that no, he can't do it, it must be Mama or Dada. I am starting to wonder who is in charge around here...