Self justification requires willful ignorance
If you desire to justify yourself in any matter, the satisfaction of this desire requires you to be willfully ignorant. Why? Because in reality, every man at his best state is altogether vanity, which is less than nothing. But if you want to be something, it follows that you desire an appearance that is contrary to reality. And to justify yourself in this appearance, you need to convince yourself in spite of the truth. Hence, your willful ignorance.
This willful ignorance ensues from your selective gathering of supporting evidence, by accepting all favorable facts while rejecting the ones that are less favorable or even contrary ("cherry picking"). This selection is not based on reality, but rather on your desired appearance.
From this subjective perspective, you can control your "evidence threshold". This "threshold" is the amount of evidence that you need to convince yourself about something. The adjustment of this threshold, either by lowering the bar or raising the bar, allows you to justify yourself in your decision to either accept or reject something in spite of reality.