A colleague of mine (let's call him Bob) sent out a question to the rest of the team:
Does anybody have a copy of xyz.exe?
Hi, Bob. I found a copy on \\scratch\temp\bob\xyz.exe
(A few years earlier, Bob had sent mail out to the team saying "Hey, I found this cool program xyz.exe. I copied it to \\scratch\temp\bob\xyz.exe." So he answered his own question two years in advance of asking it. All I did was act as a forwarding service.)
I was reminded of this story when a different colleague found himself in need of a little script to accomplish some task, so he fired up Notepad and gave it the name of the script he was planning on writing. But instead of being asked "Cannot find the file. Do you want to create a new file?", he got a Notepad window with the contents of exactly the script he wanted to write.
Turns out he had already written that script and given it exactly the same name.
At least he realized that he had already written the script before he started writing it the second time!