Reasons such as curiosity, amazement, and stimulation are why "we do such things." Fundamentally, though, sadism (and masochism) as defined in the leather community allow us to safely, sanely, and consensually explore our "Dark Sides". That is why I say "wholeness". To repress and deny that we have dark sides to our personalities is to deny stark and very "real" reality. To be "Pollyanna" is foolish, dangerously foolish at that.