I can't speak for everyone. I've had three dogs in my life. Two Scottish Terriers and one Beagle
Domesticated obviously but it goes well beyond that when you live with them for a time.
The Terriers are most recent in my life and they are certifiably nuts. Meaning, you do need a leash
at all times or you face a law suit via dead dog/cat.
There is no fear, in fact it's the opposite. Any dog twice the size is in for a fight.
I have not let it get to that point and it probably would not go well for the smaller dog
but there is no reasoning.
It's amazing that all this breeding has not tamed the beast beneath.