"Did I do anything wrong today," he said, "or has the world always been like this and I've been too wrapped up in myself to notice?" - Douglas Adams

A common mistake that people make when trying to design something completely foolproof is to underestimate the ingenuity of complete fools.

It's not the fall that kills you; it's the sudden stop at the end.

The idea was fantastically, wildly improbable. But like most fantastically, wildly improbable ideas it was at least as worthy of consideration as a more mundane one to which the facts had been strenuously bent to fit.