I feel certain that most dogs have an inner doggie sense that tells them that I am a dog lover and not really a threat.. most dogs I meet seem to feel certain that I have stopped by simply to visit them and give them snacks. The fact that I have a package for the dog's people is simply a happy coincidence!
A smaller number of dogs come running out to bark sternly at me but will skitter away as soon as I take a step toward them. I keep an eye on them but they are never a problem.
Rarely I will come up on the dog who is pretty darn serious about his job and no foolin around about it. I lay on the horn and will even (if there is a number on the package) call the cnee to try to deliver the package. If no luck then yes NI1 (DOG).
Once I was walking up the path between some parked cars to the entrance of a mobile home.. when the door opened and a child inside let out the family meat-eater dog. This dog had it goin on.. full run, vicious combination growl and bark, practically foaming at the mouth. I knew I was toast if I turned. I am 6ft 4 about 220 lbs so I stood tall, raised my diad over my head as if to strike (and thought I may have to) and began yelling at this dog in my most over the top pissed off ranting voice "YOU GET BACK IN THAT HOUSE RIGHT NOW WHAT IN HE77 ARE YOU DOING YOU GET BACK!!!" I had been having a crappy day and just focused all my anger at this poor charging beast. By God if that didn't do the trick.. dog turned on a dime and ran back the way he came, still barking his head off.
Owner came out very apologetic... child was not supposed to open the door.. but said she was very impressed as nobody had ever gotten her dog to back down.