Here's a tip for you dog owners. Don't throw the ball at a tree, cliff, or body of water. Your dog will go for it. Even some humans would go for it. I know I would, if it was a good ball. You don't want to waste the throw of a good ball just because an obstacle is in the way.
Whenever I've taken my dog into the veterinarian I always get made to feel guilty by the vet. I'll be like, "my dog ran where there was some broken glass and cut his paw," and then they look at you accusingly and ask, "why did you let him do that?" I don't know, vet. Maybe because he's a one hundred and twenty pound saint bernard so he does whatever the hell he wants. Even if he was a small dog, you can't help these dogs from being stupid every single moment of the day.