I'll respond to several posts here, so if there's non-sequitors, that's why.
First, about the CPF rant... that's exactly why I'm here! I've never been a member there, but I often find their threads in search results. I was thinking of signing up there, but read their rules page first, and it made me realize that they were, indeed, as much of assholes as they sounded like. Replace "banned" with "disappeared", and the rules reads like a banana dictator's human rights report... Question why someone was disappeared, and you will be disappeared too. etc.
I've found the vast majority of unpleasant dogs were raised that way by their owners, often intentionally. People want guard dogs, and raise their dogs to dislike everyone. Or they just neglect and abuse them. This is especially a problem with pit bulls around here - there's nothing genetically wrong with them, but thousands of people buy them, then leave them outside and randomly beat the crap out of them, because they want a "tough" dog so they can be cool... the shelters here are full of pit bulls that ran away from their abusive owners, but are so scarred (mentally and often physically) that they're hard to adopt out. And then there's the dope growers (most growers are perfectly normal people, but there's always a few idiots mixed in with any group) and homeless (same thing) who intentionally train them to attack anything and anyone that comes near them...
Yes, yelling works on completely untrained dogs. "I'm being yelled at" is understood in any language, human or animal. It lets them know that you're going to argue back, or that you understand them. Some dogs seem to act aggressive to weed out their friends and foes, too, as a test to see how you respond. Yes, dogs do think like that - their understanding of social responses can be surprisingly high. Then again, some dogs are just mean. But they're really rare.
It always annoys me when I hear about specific breeds being banned.... there is NOTHING WRONG with pits or rots. Both are very friendly dogs that are exceptionally good with kids, in fact. There is, however, something wrong with a large portion of their owners. People who want to raise/ruin a "tough" dog start with a breed with a reputation, thus furthering the reputation when they succeed. Even wolves (my favorite breed.. and me! woof!) can be quite nice dogs, although they tend to dislike strangers more than some breeds.
I've found most animals seem completely unfazed by lights. Some will look the other way, but that's about it. I've tried strobe mode on raccoons, rats, dogs, cats, and birds, and none of them cared in the slightest.
--Bushytails