If there is a possibility of several things going wrong, the one that will cause the most damage will be the first one to go wrong. If anything just cannot go wrong, it will anyway. If you perceive that there are four possible ways in which something 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.
Mother Nature is a bitch. Murphyish Military Laws Never share a foxhole with anyone braver than you are. No battle plan ever survives contact with the enemy. The most dangerous thing in the combat zone is an officer with a map. The problem with taking the easy way out is that the enemy has already mined it.