If anything simply cannot go wrong, it will anyway. If you perceive that there are four possible ways in which procedure can go wrong, and circumvent these, then a fifth way unprepared for, will promptly develop. Left to themselves, things tend to go from bad to worse. If everything seems to be going well, you have obviously overlooked something. Nature always sides with the hidden flaw.
Every solution breeds new problems.
It is impossible to make anything foolproof because fools are so ingenious. Whenever you set out to do something, something else must be done first. An expert is one who knows more and more about less and less until he knows absolutely everything about nothing. May the wind be always at your back, May the sun shine warm upon your face, The rains fall soft upon your fields and, Until we meet again, May God hold you in the palm of his hand.