My 2 1/2 year old son suddenly entered his "terrible twos" phase in the last couple of weeks. He always does the exact opposite of what we ask him to do or not to do. It struck me that his behavior could be described as "hyperactive" and that if an older child acted this way in school, perhaps the teacher would recommend drugs. But he's really just acting like a normal boy.
Gotta laugh, 'cause I pretty much raised my brothers and sister. That's the age when they learn the concept of "no" (meaning, THEY can say "no")