The more I wind up in disagreements with people, either IRL or on the interwebs, the more one thing strikes me. The biggest impediment to people considering an argument that opposed to their own is convincing them that their experience is not the universal experience.
We all have a world view that is a product of our surroundings, experience and path. Some of us who are more opinionated draw upon that background when judging any new scenario or situation. But when faced with opposing views people either stick to their guns, insisting they have the experience to accurately assess the situation, or consider that the views being put forth by another person could have merit even though the conflict with their own worldview.
That ability to stop and listen to a perspective that wouldn't have occurred to you is rarely instinctual and downright appalling for some to consider. I wish I did it as much as I should, but damn, does it open your eyes.