Holy cow, I wrote a book!
One source of cheap amusement is searching for spelling errors
in the registry.
For example, one program tried to register a new file extension,
or at least they tried,
except that they spelled Extension wrong.
And they wonder why that feature never worked.
My discovery was that my registry contained the mysterious key
After some debugging, I finally found the culprit.
There was a program on my computer that did the equivalent of this:
RegCreateKeyA(HKEY_CURRENT_USER, (PCSTR)L"Software\\...", &hk);
One of my colleagues remarked,
"With enough force, any peg will fit in any hole."
I suspect that the code was not that aggressively wrong.
It was probably something