I work as a software engineer.
One day, with utmost confidence, I modified some code to add functionality to a particular application.
My modifications worked to my satisfaction. The client, having reviewed the changes, was also satisfied.
Later that day I came across information that led me to doubt the validity of the code I’d written.
After a few minutes of debate I decided to double check the changes I’d made.
Minutes (less than 5) after that decision was made, but before I got a chance to even look at the code in question, I received a call from that once-satisfied client who was now less-than-satisfied.
The client informed me that my changes had, “disappeared,” and then she asked, “What did you just do?”
After many years of investigation I’ve figured out how to answer her.
What did I just do? Effing Magic.