One dog I've encountered twice...an intact chocolate Lab who seems fairly aggressive about chasing me...at least his barking and slobbering seems aggressive. He runs in front of me and then tries to circle back on me. A little scary, but I told him in a loud voice to back off and he seems to listen...or maybe I'm just getting far enough out of his territory that I'm not perceived as a threat.

As a dog owner (three Bernese Mountain Dogs - big beautiful animals) I am well aware that it is owners responsible for these situations. My dogs would never be allowed outside without a fence. They are rarely outside without someone being there with them.