heart of stone

Those who are far from insane often act in an irrational manner. Don't excuse such conscious and deliberate actions with so convenient an explanation as insanity.

When she gave him a puzzled look, Zedd opened his hands in a gesture of pained frustration at an old dilemma he had seen all too often.

All sorts of people who strongly want to believe in something are frequently unwilling to see the truth no matter how obvious it is. They make that choice.

[from Phantom by Terry Goodkind]