Sometimes, sometimes it's just not paying attention.

I live in an area where people just let their dogs and cats roam(people just don't really care, "oh, it's a small Southern town, it's just how we are!"), and they're absolutely awful for running out at the last second. Even with me slowing to a crawl, I've almost had incidents where one decided last minute to turn direction into the road, and had to slam myself to a stop so I didn't catch a tail/paw.

There's a terrifying amount who either don't slow, or somehow don't notice the 3 bright white Great Pyrenees running full bore down the hill.