1. If anything can go wrong, it will.
2. If there is a possibility of several things going wrong, the one that will cause the most damage will be the first one to go wrong.
3. If anything just cannot go wrong, it will anyway.
4. If you perceive that there are four possible ways in which something can go wrong, and circumvent these, then a fifth way, unprepared for, will promptly develop.
5. Left to themselves, things tend to go from bad to worse.
6. If everything seems to be going well, you have obviously overlooked something.
7. Nature always sides with the hidden flaw.
8. Mother nature is a bitch.


9. Murphy was an optimist.
10. You can't win.
11. You can't break even.
12. You can't even quit the game.
13. Just when you see the light at the end of the tunnel, the roof caves in.
14. Nothing is impossible for the man who doesn't have to do it himself.
15. Any given program, when running, is obsolete.
16. Any given program costs more and takes longer each time it is run.
17. If a program is useful, it will have to be changed.
18. If a program is useless, it will have to be documented.
19. Any given program will expand to fill all the available memory.
20. The value of a program is inversely proportional to the weight of its output.
21. Program complexity grows until it exceeds the capability of the programmer who must maintain it.
22. In nature, nothing is ever right. Therefore, if everything is going right... something is wrong.
23. Fuzzy project objectives are used to avoid embarrassment of estimating the corresponding costs.
24. A carelessly planned project takes three times longer to complete than expected; a carefully planned project takes only twice as long.
25. The effort required to correct course increases geometrically with time.
26. Project teams detest weekly progress reporting because it so vividly manifests their lack of progress.
27. Computers are unreliable, but humans are even more unreliable.
28. Any system that depends upon human reliability is unreliable.
29. Undetectable errors are infinite in variety, in contrast to detectable errors, which by definition are limited.
30. Investment in reliability will increase until it exceeds the probable cost of errors, or until someone insists on getting some useful work done.
31. There is always one more bug.
32. Profanity is the one language understood by all programmers.
33. Not until a program has been in production for six months will the most harmful error be discovered.
34. Job control cards that positively cannot be arranged in improper order will be.
35. Interchangeable tapes won't.
36. If the input editor has been designed to reject all bad input, an ingenious idiot will discover a method to get bad data past it.
37. If a test installation functions perfectly, all subsequent systems will malfunction.
38. If builders built buildings the way programmers wrote programs, then the first woodpecker that came along would destroy civilization.
39. The probability of anything happening is in inverse ratio to its desirability.
40. The amount of expertise varies in inverse ratio to the number of statements understood by the general public.
41. Under the most rigorously controlled conditions of pressure, temperature, volume, humidity and other variables, the computer will do as it damn well pleases.
42. It works better if you plug it in.
43. Experience varies directly with equipment ruined.
44. Anything that begins well ends badly.
45. Anything that begins badly ends worse.