"Have you ever been in traffic behind someone who doesn't move when the light turns green, so you honk your horn, then you realize the car is stalled and there is nothing the driver could've done?"
"Yeah, I've honked. It's embarassing," I said.
"Most disagreements are like my example. Two people have different information, but they think the root of their disagreement is that the other person has bad judgement or bad manners or bad values. In fact, most people would share your opinions if they had the same information. If you spend your time arguing about the faultiness of other people's opinions, you waste your time and theirs. The only thing that can be useful is examining your assumptions and adding to each other's information. Sometimes that is enough to make viewpoints converge over time."
-- Scott Adams in God's Debris