Unless the dog is trained to fight and is commanded to attack you, the only reason a dog will attack you is because you're not alpha -- with the exception of if you're threatening the dogs master or offspring, then it doesn't matter. To make things worse, most people look a dog directly in the eyes. Big mistake. To dogs, that's a challenge. So, if you do look at a dog in the eyes, you'd better be alpha. Dogs will go as far as putting their teeth on you before they'll back off. They won't bite down. They'll basically nip at you to see if you're going to back down. If you don't, it makes the dog shit his pants--metaphorically speaking. Don't flinch.