While most large dog owners realize by the time their puppy is several months old that obedience training will be important, small dog owners sometimes neglect the standard obedience training. After all, when your three-month-old Lab jumps up, visitors brace themselves or fall down. When your three-month-old Chihuahua does it, it seems cute and appealing and how would she ever get her head high enough to be scratched otherwise? It is true that small dogs are unable to perform many of the behaviors that make large dogs unruly to live with if they don't have some obedience, but small dogs need obedience just as much as large dogs do.
Without structure to their lives, small dogs can become insecure. If your small dog doesn't develop self-control, she is apt to become yappy and hyperactive. Furthermore, little brains need to be worked just as much as big ones, and small dogs who are left without mental activity will become bored and potentially destructive or anxious.