Here's the problem when you get a dog from the shelter. You might be getting a perfectly normal dog, or you might be getting a demon dog from the hell dimension. You just never really know until you take them home and their face contorts into their demon form. That's the risk of rescuing something, I guess. That's why I only go to breeders who specifically breed hell dimension demon dogs.
I love seeing slow motion shots of dogs grabbing for food. There are entire picture books dedicated to this craft. You can go to the bookstore and flip through one, never buying it. I would love to see a human-based book about this, but humans don't eat fast enough. The thing that makes it so great for dogs is that they dark towards the food so quickly that their cheeks look like sheets in the wind.