[QUOTE]Unprovoked dog agression is just instability and weak nerves in my opinion.[/QUOTE] 99.9% of the time it is, but good dogs can have their actual predatory instinct misdirected towards other dogs, and then it's definitely got nothing to do with fear or weak nerves. I've had one genuinely dog aggressive dog when I was a child, badly raised by my dumb dad. When it was fairly young it got confronted by a large rottweiler which it promptly crash tackled and half killed, my dad was so sure my dog would be killed by the rott and so blown away by the spectacle of the rott being completely obliterated by a smaller dog that he praised my dog and congratulated him for his efforts. Something he basically never ever did otherwise, and from then on the dog just wanted to eat dogs (was never socialised at all as well, keep in mind this was the 80s, pretty sure the word socialised and dogs had never been used in the same sentence at that point). It definitely was the most extreme opposite of weak nerves imaginable, but when it saw another dog it wanted to kill it. No hackles, no growling or barking, it just desperately genuinely wanted to get it and kill it, and it would whimper with frustration when it was restrained and prevented from doing so. It treated dogs just exactly like it treated cats and rats and possums and rabbits etc. They were prey. It's very rare for a dog to be like this, however this is how gamebred apbts are manipulated into fighting like they do. To them a fight isn't a test of dominance, there's none of that awkward social aspect, it's just pure and simply trying to kill the other dog as though they were prey. Dogs naturally all perform at a higher less reserved level against prey. However you're basically right, normal dogs that don't view dogs as prey, are inclined to "speak dog language" and be citizens of dogdom, yet are dog aggressive unprovoked, are just nervey and insecure. Most of my dogs (and they were all bull and/or mastiff based) have been totally relaxed around other dogs and not inclined to start anything, even inclined to tolerate a lot more crap from other dogs than you could reasonably expect, and then you would expect from any other kind of dog. Because bull/mastiff type dogs are actually capable they're also the most secure and least liable to feel threatened by aggression from other dogs. It's why cesar milan will often take a pitbull with him to a dog aggressive dog's house to help rehibilitate it.