John,
>> Others are ready to fight and /or play as they pass other dogs.
With my cat, "fight and/or play" are a lirttle too similar. He used to bite and scratch wjenever in a jolly, affectionate mood. It finally sank in how much we DID NOT like that, so he agreeably changed over to a very charming no-claws boxing and just-very-gentle biting.
Until he gets excited. Then it hurts again. But every time, he seems puzzled that we scold him for being AFFECTIONATE.