The trouble with kingdoms of heaven on earth is that they're liable to come to pass, and then their fraudulence is apparent for all to see. We need a kingdom of heaven in Heaven, if only because it can't be realized.
This horror of pain is a rather low instinct and... if I think of human beings I've known and of my own life, such as it is, I can't recall any case of pain which didn't, on the whole, enrich life.