To the comment of yelling at a dog . Have you ever noticed that dogs can hear noises from inside of the house , people walking across the street,the local garbage truck when it is a block away ,a cat walking by your house . yelling at your dog may help relieve your tension but is not necessary for the dog to hear what you want him to do.A soft spoken command to a well trained animal should be enough ,I believe that getting upset and yelling will just upset the dog.Have you ever seen a dog cower when yelled at?