Why can't we have a GOOD dog?

I went for a walk today during my lunch break, and out of nowhere a big alaskan malamute-type dog comes barrelling out of the shrubbery towards me. I'm alone, and based on my experience with Sam, I've come to fear the (un)reliability of dog behavior. But it turns out this dog (her name, as it turned out, was Sasha) was a very nice, friendly dog!

Sasha followed me to the end of my walk, and back to my workplace. The birds were chirping, she was off sniffing one way, then would look back to make sure I was still there, then go off sniffing the other way-- always keeping me in her sights. We ran into a few other dogs along the way. Sasha was very friendly (what a concept-- Sam can't stand other dogs). For a good half hour, I was the (imaginary) proud owner of a beautiful, obedient dog named Sasha.

Well, in the end, I called her owner (whose number was on Sasha's collar), and she came to retrieve her dog. Sigh. It was nice while it lasted