Mechanic's Logic

A group of us were working on a project and suddenly something was wrong with the code. Immediately one of the coders said "What was the last change that was made!? Put it back the way it was!"
I was laughing inside, because we frequently used this logic back when I was a teenager. You always figured that the last thing that was done was the culprit. We summed it up well in a situation where my junker car wouldn't start one morning. We all scratched our heads about why the car worked the day before, but now wouldn't start. "What was the last thing you did to the car? " my brother asked. "I put air in the tires. " I replied.
"Well, then let the air back out!" he exclaimed, as if the issue was patently obvious....