I have to say we are just as guilty of the negativity, not listening to "reason" and generally ignoring what others are saying to us. It is a reflection of self as far as those that are in our lives. There are a couple of lessons I learned early on in my recovery, that is the time I decided my life needed to change.
We attract those that serve our needs. If there is something unfulfilled in childhood we live our lives to meet that need or needs. The parent who was in some ways neglectful, for instance. Our jobs, our friends, our activities and hobbies are all a reflection of our early life lessons.
Those who are negative, living self-destructive lives are seeking to meet needs unmet. To prove they are not worthy, not loveable, yet begging to be worthy and loveable. It is an instinctive life, one that is not understood by those surrounding him or her, nor by the person living that life.
Fear is a powerful companion. It controls all aspects of life, the thoughts, decisions, ideas, lifestyle. It keeps one caught in addiction. Because that is ultimately what it is, addiction. Addiction is a tool to justify life as it is at this moment.
The person caught in this cycle is lost to understand, to comprehend what you say to him or her as a way out of this prison. The more you talk, the harder you push, the more you negate his or her existence, the harder that person is going to hold fast, just like you hold fast to your position.
Let go, release with love, walk away, be supportive. Let that person know that he or she is loved, no matter what. Acceptance is the key. Stop trying to figure it out. You won't. It is not your life experience. And remember something about this person is triggering you, why? Introspection is a powerful tool. It helped me to release and still love the person. She has not changed, so it is. I have.
Bless you on your journey of exploration.