A friend in New Zealand used to have the dumbest farm dog we've ever met.
He would regularly turn up on neighbouring farms - lucky not to be shot, having got out of his harness and hitched a ride in the back of their ute, normally unseen. Failing an available ride, he would just run through fences, wood splintering in his wake and ignore all other animals, but of course a field of sheep will panic when they see a dog hurtling towards them, as they don't know he will just run on and out the otherside...
He just liked people, and the more he could meet the better. A shame therefore he looked and sounded like an angry prize fighter all the time, when all he really wanted to do was lick you to death...
(He could also crap while running, so he didn't have to stop. Quite a feat if you can manage it...)