do you immediately distrust that person?
i had the cable guy out earlier this week, and kept the puppy caged up. she doesn't really bark at anybody...occasionally a squirrel thats teasing her, but not a big barker. i've read that GSD's become more 'pack aware' and bark and knocks on the door and such around 2 yrs. old, if they haven't before. i'm sure some never do, but...anyway.
so the cable guy gets there, comes in, realizes it isn't gonna be as easy as he hoped, and is like, "sonofa*****!" i look at my friend like, "wtf is this guy!??!" he ended up being nice enough, just a bit rough around the edges

little different too, but i digress
so the cable guy is in the backyard running lines...shes whining her ass off, so my g/f lets her outta the cage to go outside. i put her leash on her and take her out back...she notices him and starts barking her ass off...i dunno if she was excited, didn't like him, or didn't like a stranger in her backyard. i swear she reminded me of a police dog wanting to go after a suspect!
she calmed down after i told her to, but still kept a wary eye on him...
anyways, if your dog doesn't trust somebody, does that affect how *you* view them?