Behaviours
Some behaviours that dogs display are instinctual such as the prey drive but many are learned and can become obsessive. An example is twirling on the spot. It may be cute to watch but this behaviour indicates an obsession which is not healthy. Many owners tolerated all kinds of behaviours which really are best eradicated. It is up to your what behaviours you can put up with. But if it actually impacts the mental and physical health of your dog, then it needs to be addressed. Separation anxiety is a prime example.