Ownership is not limited to material things.  It can also apply to points of view.  Once we take ownership of an idea—whether it’s about politics or sports—what do we do?  We love it perhaps more than we should.  We prize it more than it is worth.  And most frequently, we have trouble letting go of it because we can’t stand the idea of its loss.  What are we left with then?  An ideology—rigid and unyielding.

Dan Ariely, Predictably Irrational: The Hidden Forces that Shape Our Decisions, New York, 2008, pp. 138-139