How to Find Promising Areas to Find Secrets

There's a tricotomy between truths that are easy, difficult or impossible. We don't really want to go after easy truths because we think lots of people already have those. And if you go after something that's impossible, you're not going to get zero to one either. So ideally, we're interested in secrets that are not small, not silly, not esoteric. But my typically preferred shortcut is to ask these sort of psychosocial questions.