The Norfolk terrier can be a loyal, hard working breed, but the potential Norfolk owner should be cautioned of a few issues that may rear their ugly heads during the training process, as well as potential problems that may come as a result of improper or neglectful training.
First of all, as is advised in any and every instance of bringing a new dog into your home, the individual dog's personal history should be investigated. As with any breed, an abusive or neglectful childhood may tragically damage the Norfolk terrier's potential for being trained as a healthy, happy family, show or work dog later in life, perhaps even irreparably. While a mistreated dog might not necessarily be completely unsalvageable, a dog with a rough history will almost certainly be quite a challenge, and training a troublesome dog is not at all recommended for first time or amateur trainers.
The breed is known to be so incredibly brave that scars are not even counted as negatives in show. Rather, in the eyes of the judges, the scars are seen as medals of Honor. From that alone, one might guess that a primary training concern might be the dog's willfulness, and that guess would be correct. If not taught early on the importance of proper respect for their master, the male Norfolk may wind up being disobedient in adult life. Short of any problems stemming from mistreatment, this tends to be the main concern with terrier's who aren't trained properly.
This willfulness may also become a problem throughout the training process itself. Again, though, short of any serious mistreatment issues, this is nothing a firm hand can't help. As silly as it sounds, the main thing to remember when butting heads with a stubborn dog is to simply be more stubborn than the dog.
It's an outrage and a shame that so many purebred dogs suffer from abuse and neglect thanks to puppy mills more concerned with quantity than quality, and breeders who aren't above using inbreeding to keep the lineage pure. These mistreated Norfolk terriers can be hostile or mistrusting of people, and Norfolk's who have suffered serious neglect are likely to become feral, so again the importance of researching the dog's history must be stressed.
One more note, the Norfolk terrier is said to have absolutely zero traffic sense. Any Norfolk owner must make absolutely certain that their dog obeys commands and can be leashed without becoming agitated or impatient (as might happen if their stubbornness isn't dealt with early on). All too often, disobedient and runaway Norfolk terrier's run across a busy street and meet an untimely, tragic demise. If only for the dog's own good, the Norfolk terrier must be taught the importance of trusting and obeying their human companion.