You’re walking your dog when an off-leash Lab puppy comes sprinting your way. Knowing that your dog is about to freak out, you shout, “Call your dog!” in the vain hope that the caregiver will (a) call her puppy and (b) actually be able to get the puppy under control. The common response, “Don’t worry, she’s friendly!” sends your pulse soaring. It’s meant to reassure you, but few phrases are more terrifying when you know your dog is going to bark, lunge or worse.