1. Nothing is as easy as it looks.

  2. Everything takes longer than you think.

  3. In any field of scientific endeavor, anything that can go wrong will go wrong.

  4. If there is a possibility of several things going wrong, the one that will cause the most damage will be the one to go wrong.

  5. If anything just cannot go wrong, it will anyway.

  6. If you perceive that there are four possible ways in which a procedure can go wrong and circumvent these, then a fifth way, unprepared for, will promptly develop.

  7. Left to themselves, things tend to go from bad to worse.

  8. If everything seems to be going well, you have obviously overlooked something.

  9. Nature always sides with the hidden flaw.

  10. Mother Nature is a bitch.

  11. It is impossible to make anything foolproof, because fools are so ingenious.

  12. Inevitably, you will forget one of your laws.

  13. The summary:
    If anything can go wrong it will.
    (And at the worst possible time)