It is best to view selection for specific behaviors as a risk assessment analysis. Breeds that have been selected for one or a few particular traits may be more at risk of developing undesirable variation for those behaviors. My analogy would be if I pulled into a parking lot one day and somebody steals a parking place from me. This does not mean I'm going to the parking lot with a gun and shoot someone. So the signs were there - let's see if we can see some of the classic ones.
Intact males are more likely to exhibit dominance aggression than neutered males or females.
Dominance aggression and protective aggression are the number 1 and number 2 causes of treatment by behaviorists. The dog is challenged by a stare or a bump or body blocking and then each dog behaves in reaction to what the other dog did. A characteristic of interdog aggression is that aggressive intention is not displayed to other animals - the dog may live amicably with cats and horses. Most of us have dogs who display signs of territorial aggression - our dogs bark at someone at the door, protect the car, bark as people pass on the sidewalk. For dominance aggression, in contrast to protective aggression, there is more growling, snarling, biting, and staring.