Yes, I remember repeating this pablum, "What you don't know can't hurt you." I don't remember why this thought was hammered into my head but obviously there really are many things that I can't know and that, if I did know, could have the potential to hurt me I would imagine, so there are some things that there would be no reason to explore, some questions worthless of asking, some answers more damaging than helpful. I really don't understand why some people seem to have a problem with this policy. I think it is a smart policy and makes a lot of sense.
Sure, some things we need to know for navigation purposes but also some things are not necessary. Delegation of duties, division of labor, etc., all of these things are beneficial in the long run.