I have to disagree Lee I think that fear makes you fight that much harder thinking you can die seperates the pups from the dogs so to speak..... fight or flight is revolved around the fear response I don't think anything will put as much into it without some level of fear. plus fear also releases endorphines for pain and adrenaline for stamina and strength fear is needed that's why its there....I'll take a dog that can harness there fear over a dog that is afraid of nothing any day