You are not going to believe what I am about to tell you - The Oatmeal

The Oatmeal explains the backfire effect like only he can

Guy’s a friggin’ genius, I tell you. The facts have been selected in a way to really trigger people from the States, but maybe this even makes me appreciate it more.

The backfire effect describes that when contradictory evidence is processed, your beliefs (which are being contradicted) get even stronger. (good article at the Boston Globe archive)