The reason for our conservatism, which may impress some people as extreme, is that it is entirely predictable that people will occasionally panic, but not at all predictable when this will happen. Though practically all days are relatively uneventful, tomorrow is always uncertain. (I felt no special apprehension on December 6, 1941 or September 10, 2001.) And if you can't predict what tomorrow will bring, you must be prepared for whatever it does.
