A "Showerthought" is a simple term used to describe the thoughts that pop into your head while you're doing everyday things like taking a shower, driving, or just daydreaming. The best ones are thoughts that many people can relate to and they find something funny or interesting in regular stuff.
Or, the less mean dogs were lucky that humans only killed the threatening ones?
Luck's got little to do with it. Dogs were selectively bred for those traits.
Like... wolves?
Most wolves are actually terrified of humans and would probably run away if they see you. You should still be careful in areas with wolves though.
Do you know if that's a modern change or if it's always been the case?
I don't know. I heard it in a documentary about coyotes a few years ago.
Maybe, but coyotes are not wolves.
The wolf fact was in the documentary to compare the two. When a coyote and wolf breed, the offspring is bigger than a typical coyote and not as afraid of humans as a typical wolf.
Little dogs are mean because shitty humans think “aw he’s so itsy bitsy I don’t have to train or discipline him at all!” Totally ignoring that (a) a dog needs maintenance discipline to be emotionally secure, and (b) aggressive little dogs are unhappy little dogs.
My mom and sister have chihuahuas and my grandfather has a shih tzu, they are all super sweet dogs who have ever been aggressive towards anyone. Meanwhile, a family that lives down the street from my grandfather had a golden retriever that had to be put down because it kept attacking kids unprovoked. Sure, some dogs are more predisposed to be aggressive than others but the way they are raised and the environment they live in plays a massive role in how a dog acts.
Are bigger dogs less mean, though?
From anecdotal evidence. Little to medium stray dogs are the ones most likely to snap and chase you for whatever reason. Granted, it could just mean that big mean dogs were put down ebcause they actually hurt someone compared to the abandoned dog with a napoleon complex.