Daniel Callcut in Psyche:
Knowledge is so often assumed to be a good thing, particularly by philosophers, that we don’t think enough about when it makes sense to not want it. Perhaps you’re a parent and want to give your children space: you might be glad to not know all that they do when out of your sight. Perhaps you want to reconcile politically with a group that’s committed violence: it might be easier to move on if you deliberately spare yourself all the details of what they’ve done. There are, in fact, a variety of reasons why one might reasonably choose ignorance. One of the most obvious is to avoid needless pain.
Most of us care about other people and the world at large, and that makes us vulnerable to bad news. That’s life. Nonetheless, it’s good to be self-aware about when we’re self-punishingly seeking painful or depressing knowledge about ourselves or the world, and returning again and again to such knowledge. It’s easy to become what I shall call a truth masochist.