I've made mistakes, though thankfully no huge outage-causing ones. The only "I'm going to get fired" mistake was a political one, where I accidentally emailed a report to someone, and was informed after the fact that it was a very bad thing. It's also a fallacy to believe that making mistakes in the past and learning from them precludes making many novel mistakes in the future. Kind of like the disclaimer that's always given about investing. Both the individual and the organization must simply bake in as many failsafes in their processes as possible. And even then, sometimes Murphy's Law manages to slip through all the holes at once.