Ahead of Paul Krugman this time

What took Paul Krugman ten years to figure out became clear to me in less than two years (but he's still smarter than I am):

When I first began writing for The Times, I was naïve about many things. But my biggest misconception was this: I actually believed that influential people could be moved by evidence, that they would change their views if events completely refuted their beliefs.

PK gives credit to Upton Sinclair for observing that “It is difficult to get a man to understand something when his salary depends on his not understanding it.”  Salary, campaign contributions, tribal status, etc.