1) If a computer or system is working on Monday, something has gone wrong and you just don't know about it.
2) When you don't know what you're doing, document it.
3) Computer errors must be reproduce-able, they should fail the same way each time.
4) First call tech support, then panic.
5) Experience is directly proportional to the number of systems/computers ruined.
6) Always keep a backup of your data, and hope everyone else does the same.
7) To write a program really well, have your wife/husband/Mother/Father test it.
8) If you can't get the system to match the Statement of Work (SOW), redo the SOW.
9) In case you experience doubt, make it sound convincing.
10) Do not believe in miracles--rely on them.
11) The technical term is H.O.S.E.D. (Hardware Or Software Error Detected), use it often and amaze your friends.
12) When it starts working; and hopefully it will, you fixed it in case anyone asks.
13) No troubleshooting experience is a complete failure. At least it can serve as a negative example.
14) Any expensive piece of software will break before any use can be made of it.
15) Team work is essential, it allows you to blame someone else.
This is an original post, feel free to reproduce as long as you give credit.