The best kind of laughter is the self-deprecating kind, when we acknowledge our foibles and limitations and weaknesses and are willing to laugh at ourselves. That brings us closer to an appreciation of the human condition -- we are then able to understand those faults in others. The worst kind of humor is directed at those "others" -- the people who are not like us and are thus deserving of our scorn and derision. We don't have to understand anything, except that we are better than them. Such laughter says more about us than the people we laugh at.