Why is this 3 Year Old driving me bonkers?!!?

For all the moms out there I hope you are able to relate to this:

Why is the new "two" three years of age?!?
The oldest child that I nanny just turned 3 a week ago, and I have to say he is driving me bonkers!!!!!
Why don't 3 year olds listen? His one year old brother listens better then he does, which is just crazy, and do all three year olds figure out how to fight, kick, and hit right when they turn 3? This child has turned into a beast!! Help me?!?!