Argumentation

People tend to get into a lot of arguments online, both nasty and the one where you're trying to people see your point of view. What keeps people from just arguing constantly and never moving forward past their points of view? Well, obviously it depends on the context; if we just look at internet comments, it might make one despair about people's ability to look beyond their point of views. But even on some forums how fairly well-educated, well-spoken, and just reasonable people who are willing to change their mind.