My boy is 4 I've had him since he was 7 mths. His behaviour was appalling but over time he's improved 100%. However, although h e isn't aggressive, if I allowed him to approach another dog he would show aggressive behaviour, growl and bark. The noise understandably frightens owners and I find it easier to make him sit quietly to allow other dogs to pass before continuing our walk. Is this behaviour a result of not being socialised as a puppy by his previous owners?