I have a 5 month old male shepherd and the other day a dog off leash ran up to us and my dog flipped out.. growling and crying and showing teeth and throwing his body all over the place. He goes to petsmart with me all the time and does fine with those dogs. He will bark on occasion when he sees another dog and wag his tail but i know sometimes that doesn't mean hes happy. My question is should his reaction to the other dog be like this? What can i do to help him react better? The other dog wasnt any bigger then he is. He is 5 months and 60 lbs.