Stub-born: /ˈstəbərn/ adjetive
having or showing dogged determination not to change one's attitude or position on something, especially in spite of good arguments or reasons to do so.

Have you ever referred to your dog as stubborn or had another trainer say this about your dog? Is the dog actually stubborn or is the human? If we keep doing something that is not working and we know it isn't working then aren't we being the stubborn ones? Especially if we know there are other methods that may work better?

First we need to find proper motivation. Just like we may be motivated by different things, so are dogs. Using my own dogs as an example I have one that is ball or toy motivated. She will do anything, absolutely anything, for a ball or squeaky toy. I have one that is very food motivated. Especially when it comes to cheese. Then I have one that will do anything to get a drink of water from a water bottle. Last, our newest arrival, changes what motivates him.  Sometimes it's food and sometimes it's attention.   Motivation can change, depending upon their mood (and if they are hungry). Learning what motivates them gives us a better relationship, mutual respect and a less frustration.

What doesn't motivate? Punishment.  Punishment suppresses, it does not build a relationship based on respect or trust.  It also causes confusion and can lead to fall out behaviors of anxiety, fearfulness, and even aggression.