Zeus has been around kids ,People,Dogs an cats from the first day I brought him home. Loves them all. But does have great fun chasing the cats but doesnt try to hurt them.He hasn't been to dog parks or anything because I live way out in the country. But he has Lots of play time an training in his own yard. But every time we go out side his hair is always up. an today I was trying to walk him on the road.an he was so very skittish an kept jumping on me an he knows he is not allowed to jump on people.He is not quite 4 months he never barks at anything. is this common or am I doing something wrong? He loves playing with the other Dogs an doing what puppys do. But it was almost fear.I of course got him for a Guard Dog. But should I worry he will be aggresive out of fear?