Bias much of everything.
Having this in mind, this is the best paragraph I read today.
"We feel a deep pleasure from realizing that we believe something in common with our friends, and different from most people. We feel an even deeper pleasure letting everyone know of this fact. This feeling is EVIL. Learn to see it in yourself, and then learn to be horrified by how thoroughly it can poison your mind. Yes evidence may at times force you to disagree with a majority, and your friends may have correlated exposure to that evidence, but take no pleasure when you and your associates disagree with others; that is the road to rationality ruin."
Tip of the hat to MR for the pointer.
Read all here.