The were easy to handle, responded well to being on leash (fewer balks, calm enough to eat), and they were the least fearful of potentially scary stimuli. (pethealthnetwork.com)
To prevent dogs from becoming wary of children, men, strangers, skateboarders, other dogs, loud noises, vacuum cleaners, nail clippers, collar grabs, etc. etc. etc., take your time when exposing your puppy, adolescent, or newly adopted adult dog to novel (unfamiliar) stimuli, settings and situations and make sure you classically condition your dog not only to tolerate, but also to thoroughly enjoy all of these potentially scary stimuli. (dogstardaily.com)
Among other functions, it is part of the brain's reflexive system and it is good at quickly generating emotions like fear and anger when we're presented with new, out of place, or scary stimuli. (ammdividendletter.com)