Here is a common situation at my house. My 5 1/2 year old picks up a toy and suddenly the 3 year old decides he wants it. Cue the screaming. Then the older child realizes the leverage he has over the younger one, and proceeds to hold on to the contested toy long after he has lost interest in it, just to prevent the younger child from having it. Screaming continues and Mommy starts to lose it. So the 5 1/2 year old crosses a line from being innocent to being something less than innocent, but not quite guilty. I'm not sure how to handle this.