Farm Dogs

I read Marty's post about his dog. It got me to thinking about what makes a good farm dog. At least for me. Number one and foremost, they must have no intrinsic value. Yes, worthless. Ours always have been. They should never run off. That is easy for a farm dog to start. They must be friendly, curious, and keep their feet on the ground around people and cars. It's nice if they'll come up to greet you on your return home. Ours do, (we have two) but it's because when we go out to eat, our doggy bag is for the dog. You must have a good story about how you ended up with him. "We bought him" is not satisfactory. One of our most beloved dogs, kept running over here from the neighbors. I told Marilyn, "the neighbors pup is over here again, you know I think I'm ready to get another dog. Maybe a lab mix like the neighbors have". Just then Rick the neighbor drives in (we had called him about his dog) and asks, "you want that dog, he must like it here better than my place". "yeah, leave him".
He stayed here, never ran off, was friendly, performed at several 4-H dog shows {if he was on a leash} and was particularly worthless.
Andy was his name. About the most radical thing he ever did was in our shop. My brother was laying under the combine. He had both hands on wrenches, applying much pressure to a stubborn bolt when Andy walked over to him and licked him from back of his head, thru his ear, and past his eyes to his forehead. One, quick, lick. Ed called him something and it wasn't Andy, ....But it was accurate.
If Ed and I would be eating something out in the corn field during harvest, Andy would sit there and look at Ed. Ed would usually eat the sandwich, or about 3/4ths of it and then stare at Andy and with mock anger say, "Okay, here, eat it". It was always a mid air catch.
What makes a good dog for you?