I got bit by a dog a while ago and the thing that really woke me up was how unexpected it was. I generally think that I'm fairly observant and empathetic with animals. All B.S. aside I genuinely think I can tell when a dog is scared. The dog that bit me though, totally out of the blue. I saw it. No body language, no nothing - and I walked by it and next thing I knew it jumped out and bit my hand.

Since then if I see a strange dog and the option is there I keep plenty of distance between it and me no matter what I take to be it's state.