I was working for a startup that needed to update 300 machines that had just come from the factory. We had to open all 300 boxes and update them one at a time. I made a simple script that would run a folder full of shell scripts then keep track of what it ran so it would not run the same script twice. It made it so we could just plug the machines into the internet, they would query some server, download my program, and run it. It saved me from having to ssh into every machine and run commands. Well the head programmer guy saw what I did and implemented it as the main program that would update the entire machine. I didn't program anything into it to verify updates, the shell scripts did not return any indication of success or failure, and I made it in less than 3 hours. It was supposed to be a temporary program to be used for those 300 machines only, but ended up sticking around for 2 years.