The Good, The Bad, no... not bad!
I'm just going to jump right in. There are no bad animals. That's right. I said it, and I will say it again. There are no bad animals. Right about now, my readers are quickly thinking of examples where animals have been called bad or have done something really horrible to dispute this claim. What I will say to those examples is this: that's bad behavior, not a bad animal.
Labels help people get through life. We like to categorize things and people into little boxes so that we know how to behave or how to react to a certain situation; they even help us decide what we feel about a person or thing based on the label. But labels can be dangerous. Once you slap on a negative label, the object of that label suddenly becomes the label and cannot find a way outside of it. For example, if your dog does something you don't want them to do, and you say "BAD DOG!", the dog interprets HIM as being bad...not the behavior. Telling other people that he was bad and saying it over and over just enforces that you think he is a bad dog. As with a child, this gets internalized and affects their mood, their behavior, and often can bring out really bad behavior.
Some bad behavior is relative to the human who lives with the animal. Some humans don't like animals on their furniture. If the animal goes on the furniture, they think it is bad. I have seen some humans tell a dog that she was bad because she greeted another dog. For that human, the dog was not supposed to greet anyone, just walk in a straight line and that was it. What a miserable existence for that poor dog! There are exemptions, of course. A service dog must be focused only on his/her human and the environment. The case I mentioned was not a service dog.
Biting is never good behavior, but I still don't think it makes the dog bad. Biting is a natural response and instinct. When dogs are puppies they nip and bite each other in play, practicing their skills. A dog will bite to defend itself from someone or something. They also do not have hands that can grab things, so a "bite" can sometimes be just grabbing something they want. We ask a lot of dogs and other animal companions. We want them to live in our world and share our human experience without being a human. It is not fair to expect all our human ways to make sense to them. It is our responsibility to teach them and train them with kindness and compassion.
Not all animals will learn or accept everything we teach. It is up to us to see if there is another way to show them that it is important to us, or if it isn't really important we can decide to let that one rule go. Sometimes, the animal does not suit the human. Personalities don't always mix and lifestyles have a lot to do with a proper match. A high-energy dog will not do well in a house where rules are super rigid and activities are minimal or boring. Just like with a toddler, boredom creates mischief.
Finally, stop comparing your animal companion to others. Each animal is unique, has different needs, and has different personalities. It is up to us, as their caretakers, to work with their personalities so that they thrive. This creates a wonderful environment where the animal companion willingly listens to your wishes because ultimately they want to please you when they feel loved, free to be who they are, and a member of the family.
Treat every being with kindness and let go of those negative labels. We share the planet with the animals, and as stewards of the planet, we need to do better than slapping labels and expectations on other beings based on our human experience. Be kind. Show love. Learn from our animal friends. They usually think we complicate things- and we usually do.