The waterfall appeared unremarkable, unless you knew what it did: erased a prior negative memory, albeit at a cost. If you walked beneath thinking of a deceased pet, you might also forget the moment your parents were proudest of you. In eliminating a horrific car crash, perhaps you’d undo your wedding day. To erase an abusive partner, you’d obliterate that sweet memory of a first love. The loss of a child? Disremembering your sibling’s very existence. In other words, just and exclusively for those who walked through the waterfall: the possibility of greatness, accompanied by an equal risk of pain.