Murphy's Corollaries (laws) Left to themselves, things tend to go from bad to worse.
It is impossible to make anything foolproof because fools are so ingenious
Law of the Perversity of Nature (Mrs. Murphy's Corollary):
You cannot successfully determine beforehand which side of the bread to butter.
Corollary (Jenning):
The chance of the bread falling with the buttered side down is directly proportional to the cost of the carpet.