I once had a puppy that was very vicious and biting. Everyone advised me to get rid of it.
I didn't throw it away.
I taught him to be good when eating, to be good when sleeping, to be punished for making mistakes, and to be rewarded for being obedient.
Later, he became the best-behaved dog who only wags his tail at me.
Concept: The so-called dog training is actually two people who don't know how to love, teaching each other in the clumsiest way what it means to love and be loved.