If anything can go wrong, it will go wrong.
I have traced 'Murphy's law back to a Captain Edward A. Murphy, an American engineer at Muroc, California (later named Edwards Air Force Base). In 1949 he was working on a project to test the effects of sudden braking. Time after time his machinery failed, exasperated he said of his technician, "If there is any way to do it wrong, he'll find it." John Paul Stapp picked up on Murphy's phrase and used at a press conference.
As with any good idea, Murphy's Law can be adapted and extended.
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.
If you realize that there are three possible ways in which something can go wrong, and cover them all, then a fourth, unprepared for way, will miraculously appear out of thin air.
When something breaks, the parts damaged are in direct proportion to their value.
The failure does not appear until the machinery has passed its final inspection.
When you drop a part, it always rolls into the darkest corner.
Any attempt to print out this copy of Murphy's law will crash the computer.
* Examples of Murphy's Law
Your lost needle will be found by your husband when he is walking around barefoot.
The worst pupil in any class will be a school governors' son.
Uniforms only come in two sizes, too large and too small.
Vital documents that were posted with no errors, will develop errors in the mail.
Murphy's Law of DIY (Do-It-Yourself )
Any project will require at least two journeys to the hardware shop.
If you need more than one item (pair, four, etc) the probability that one will be damaged or the wrong colour is directly proportional to the desire or need of the object.
You always need more paint.
You never have enough nails, screws or glue.
The likelihood that you will complete a weekend project before the end of the weekend decreases with when you actually start the project.
Therefore: Any plumbing project started after 4pm on Sunday will require an emergency call to the plumber to get the water running again.
To estimate the amount of time needed to complete a project: estimate the amount of time needed, multiply by two and use the next highest unit. Hence: A one hour task will take at least two days to complete.