Aleksander doesn't like being surprised, especially by being smacked. He has also defended small children, even against their own parents. He tried to bite my brother when Aleksander was playing with my small nephew and my brother picked my nephew up. You never really know what a dog is thinking, so it does pay to be alert and careful. This is a good reminder to everyone.
Dogs are pack animals and they consider the family to be the pack.
Of course every situation is different. Ive only had two instances with my furbaby. He bent over to feed me a french fry and my dog snapped at me. That is NOT acceptable behavior. Hasnt happened since.