Just a little while ago, I was letting Jack out back. I live in a Philly row house. We have back yards that back up to an alley and across the alley is another back yard of the house behind us. Anyway, Jack is in the 5 foot fenced yard when one of the neighbors is walking her Neopolitan Mastiff. She yells "oh my god" yanks back on her dog's leash and starts pulling him back. Her dog barked at Jack and he barked back but I immediately told him "no barking" and he quieted down. I told her the gate was closed and Jack by no means could get to her neo. She just kept pulling and turned around and walked back the way she came. I didn't get the impression that her dog was aggressive.
That kind of stuff is starting to drive me crazy. Her neo was not that much smaller that Jack. I'm having a real hard time socializing Jack because no body will let their dogs near him.