The dog walkers are the worst. I remember almost running into some a few times. It can be really dangerous if you're coming down a hill at a high speed just when the dog of some idiot walking it decides to run to the middle of the trail, spanning the leash between the owner and the dog and making evasive action practically impossible. Fortunately, the vast majority of dog owners have the sense to avoid doing that. But I don't like the dog poop on the side, either.

Btw, that picture was taken at the juncture of the ski trail and a foot path.