Cyberjoke friday v1.992 Halloween edition

Yes it is time for another edition of Cyberjokes edition, might as well make it Halloween themed:

Q: When is it bad luck to meet a black cat?
A: When you are a mouse.
So we can make it cyber related(mine):
Q: When is it bad luck to meet a Hacker?
A: When your computer is named Murphyslaw
Halloween jokes from halloween.com
Q. What do you get when you cross a vampire with the internet?
A. blood-thirsty hacker baby
Q. What did the bird say on Halloween?
A. Trick or tweet!
1. If a test installation functions perfectly, all subsequent systems will malfunction
2. Not until a program has been in production for at least six months will the most harmful error be discovered
3. Job control cards that positively cannot be arranged in improper order will be
4. Interchangeable tapes won’t
5. If the input editor has ben designed to reject all bad inputan ingenious idiot will discover a method to get bad data past it.