As long as it can bark and sound mean, it generally does the trick! My dog is the nicest dog in the world....but as soon as somebody knocks on the door (especially at night) he goes fucking crazy. I love this dog. Knocking means it's not me, and it sets him off. He's only a 40lb pit, very small compared to his parents and won't get any bigger cuz he's the runt...but he can growl like a mofo and gets a mohawk when he's suspicious LOL. I'd hate to be the one he gets ahold of breaking into my house. I used to swing him by towels, he won't let go LOL.