I am having an agression problem with Teddy lately. Although he has been extensively socialized (at puppy rescue, dog parks, etc.) it seems like when we go on a walk no matter what he sees -- other dogs, kids, adults, bicycles -- he starts to howl and gets really tense. We've tried just walking on so he'll get the idea that this is normal but I don't know how else to reinforce the idea. If the dog, kid or person comes over to pet him he's hesitant (low growls sometimes) at first then warms up and lets them pet him. I don't want to put him in a situation where he feels threatened and I don't want anyone to get hurt either. FYI - Teddy is eight months old now in case that helps. Any suggestions? Thanks.