Index: My Favourite Quote
If your specifications are contradictory, life is very easy, for then you know that no program will satisfy them, so, make "no program"; if your specifications are ambiguous, the greater the ambiguity, the easier the specifications are to satisfy (if the specifications are absolutely ambiguous, every program will satisfy them!).

-- E. W. Dijkstra. In EWD447: On the role of scientific thought.