Alex asking Annie to let go of the ball.

I do not believe our dogs are trying to dominate us, yet they learn over time what they can get away with.  Sound like some children you know?

 
Just like children go to the parent who is most lenient, dogs quickly learn who will follow through and who will not.  They know exactly who will reward and who will not, and make choices based on this relationship.
 
Consequence drives behavior with both kids and dogs.  Think of consequences as being Positive not negative! Thanks for loading the dishes!  What a gooood boy!
When Annie learned that “Leave it”, meant Alex would continue playing with her and rewarded her for bringing the ball back, she was happy to comply!

If by chance you want better behavior from your dog or your child, try motivating them to comply and reward with something they want or like.  Many people say dogs are stubborn, however the truth is they have competing motivations, so use rewards like your pitch, food and play to help them consistently make the right choices!