What is the dumbest thing you have done at a job?

When I was 15 I got a job at a Subway. I was trained for like a week and left to run the place by myself. Now keep in mind, I was not a great salad eater and I knew next to nothing about salad dressings. The only dressing I had heard of was Ranch dressing and that's it. Literally. Well long story long, some guy came thru the drive-thru and asked for a salad with (this is what I THOUGHT I heard) a "thousand olives". So as I was preparing the salad I kept thinking now why would he ask for a thousand olives? I could come up with no other answer than, hey, the guy likes olives and he probably said a thousand olives to make a point for me not to be shy about putting olives in there. So put olives I did. I made the salad and grabbed handful after handful of black olives, piling them on top of the salad. If you had looked into the container, you would have thought it was a container for olives. I handed the guy the salad, he paid and went on his way. It was only later that I realized he had asked for "a thousand islands" dressing. The thought of him getting home and seeing all those olives in there made me bust out laughing. How his face must have looked! I was fired 2 weeks later for leaving the bread out (12 pans worth) which got hard and had to be thrown away.