Talking to the dog doesn't always work. The dogs that are not well trained and left to do their own thing without any humans disciplining them will not listen and are running totally on instinct by protecting their territory. These dogs are usually, but not always, out in the rural areas. Their owners do not care what happens to them, and the unfortunate cyclist or runner is the unknowing victim. Sometimes it takes more than a friendly "NO" to stop a charging undisciplined dog.