Not devoting enough time to the animal. People who are too busy or too lazy should reconsider getting a dog in the first place.
Getting a dog that's too difficult to handle, either because of breed or size. Some breeds are easier to train than others; some breeds are naturally more submissive.
Using the word "No" at the wrong time --If you combine the word 'No' and your pet's name or the word 'No' and the 'Come' command, you're sending mixed messages. You should always associate your dog's name with positive things.
Getting upset and screaming are not appropriate. The last thing you want is an animal that's scared of being around you.
Joining a class and then giving up after the first lesson because you didn't like the trainer. Not every trainer is a good fit for everybody. Some trainers are better with medium dogs while others are experts at managing large animals. Before signing up, ask to observe a class, see how the animals interact, the trainer's attitude, etc.
“I believe nonviolence fosters nonviolence," says Owen. "Because of the link between dog and human behavior, positive dog training contributes to helping build a world of peace for humans and dogs. When people, especially children, are successful using nonviolent methods with animals, they feel good about themselves and they are encouraged to have a kinder, more positive attitude with their friends, family, and the environment.”