Murphy's Laws for Computers

* Any given program, when running, is obsolete.
* Any given program costs more and takes longer each time it is run.
* If a program is useful, it will have to be changed.
* If a program is useless, it will have to be documented.
* Any given program will expand to fill all the available memory.
* The value of a program is inversely proportional to the weight of its output.
* Program complexity grows until it exceeds the capability of the programmer who must maintain it.
* Every non- trivial program has at least one bug
Corollary 1 - A sufficient condition for program triviality is that it have no bugs.
Corollary 2 - At least one bug will be observed after the author leaves the organization.
* Bugs will appear in one part of a working program when another 'unrelated' part is modified.
The subtlest bugs cause the greatest damage and problems.
Corollary - A subtle bug will modify storage thereby masquerading as some other problem.
* Lulled into Security Law
A 'debugged' program that crashes will wipe out source files on storage devices when there is the least available backup.
* Adding manpower to a late software project makes it later.
* Make it possible for programmers to write programs in English, and you will find that programmers can not write in English.
* No matter how hard you work, the boss will only appear when you access the internet.
* The hard drive on your computer will only crash when it contains vital information that has not been backed up.
* Computers don't make errors-What they do they do on purpose.

-ZeroOne

PS. A couple of more
here.
Also check Computer Stupidities.