Dogs running loose may have been having to fight for their lives, fight over food, or fight over territory. They would fight your dog if they thought it was taking away what it needed like food,...
Dogs are creatures that are there to keep us company. They are like a friend but a dog will (mainly) go on walks with you, play frisby (or ball) or just sit quietly and listen to you (some do bark)....
in general, there could be two realistic answers to this.
The first as a joke ... none, dogs don't have feet they have paws.
The second answer forgiving the feet/paw issue and presuming you meant...