The mythical author of Murphy's Law:
If anything can go wrong, it will.
There's even a cottage industry around this law and other derivations - see, for instance, http://www.murphys-laws.com/ as one example.
One of my favorite corollaries is
If anything can't go wrong, it still will.
AM I am surprised by the above link: it does not mention Samuel Beckett's novel "Murphy" - I always took that as the origin of the "law".
FPX: There's nothing mythical about Murphy. Edward A. Murphy, Jr. was a real person, although as much credit must go to John Paul Stapp, lesser known advocate of, among other things, the seat belt.
The original "law" is: If there are two or more ways to do something, and one of those ways can result in a catastrophe, someone will do it. This was not meant as an excuse for failure, or as a fatalistic way of explaining random events, as "Murphy's law" is commonly used in today's language. Rather, it was intended as an engineering precaution for safety by design: make it so that something can not be used wrongly by careless mistake.
The example that prompted Murphy's law was coined was a force measurement device. It could be installed two ways, but worked only when installed one way. So, of course, it was built in the wrong way around, a costly experiment was run, only to get back a measurement of zero.
A common household example exemplifying the lessons learned are polarized plugs: you cannot plug them in the wrong way around. If your DC sockets were symmetric, someone will certainly fry the circuits by mistake.
Note that this principle applies to software as well as hardware. E.g., do not put the "delete" button right next to the "print" button. Do not obnoxiate users with hundreds of silly "are you sure" dialog boxes so that they don't notice the one that executes the virus. Maybe we should collect such advice on a separate page: Murphy Software Engineering.
For their achievements, both Edward Murphy and John Stapp received an 2003 Ig Nobel Prize [L1 ].
Read the full story in the Annals of Improbable Research: [L2 ]
AMG: I highly recommend reading the article linked above: "The Fastest Man on Earth".