We’ve all done it. You are sitting on the couch watching TV and snacking on some popcorn and your dog stands there looking at you with sad eyes. So you throw a piece up in the air and he leaps up to catch it. Happily, he crunches the popcorn loudly then sits and tilts his head and you give him another. Or, you are about to sit down with a piece of pizza and the doorbell rings, more likely you go see why your kids are yelling in the other room, only to come back three minutes later to an empty plate and a dog that sits licking his lips.