Quick question on dog body language?

I'm having a little trouble figuring out the difference between approaching aggression and playfulness in dogs meeting for the first time. Sometimes it looks like one is going to be aggressive (stands very stiff, tail wags slowly, stares intently at the other dog) and they end up playing. What is the... show more I'm having a little trouble figuring out the difference between approaching aggression and playfulness in dogs meeting for the first time.
Sometimes it looks like one is going to be aggressive (stands very stiff, tail wags slowly, stares intently at the other dog) and they end up playing.
What is the difference in body language between a dog that is going to bite the other dog and a dog that wants to play?
thanks!!
10 answers 10