One morning, as I walked on the quiet, mostly wooded King Mountain trail above San Francisco Bay, a dog not much smaller than I and possessed of much sharper teeth made straight for me, growling. I tried to get away; it butted me roughly. When its owner came around the bend with a second dog, I said, the snot from the first still gleaming on my pants, “You need to keep your dogs under control.” “My dogs are under perfect control,” the woman replied with asperity. The point was clear: She could control them but didn’t care to. She…