From Avoiding Your Belief's Real Weak Points:

"To do better: When you're doubting one of your most cherished beliefs, close your eyes, empty your mind, grit your teeth, and deliberately think about whatever hurts the most. Don't rehearse standard objections whose standard counters would make you feel better. Ask yourself what smart people who disagree would say to your first reply, and your second reply. Whenever you catch yourself flinching away from an objection you fleetingly thought of, drag it out into the forefront of your mind. Punch yourself in the solar plexus. Stick a knife in your heart, and wiggle to widen the hole."

Condensed: If you catch yourself flinching away from a thought because it's painful, focus on that thought and don't let it go. If the truth hurts, it should.

This is, I think, some of the most important rationalist advice I ever got. It kept me reading OB when it was getting very painful to do so, and allowed me to finally admit that my religion was immoral, a thought I had kept tucked away in rationalization-land since middle school.