1st Day on the Job Fails

Saw a story about someone at British Airways who mistakenly activated a plane's emergency exit on their first day as a flight attendant. Slide deployed, forcing them to bring in another plane for the international flight. Cost? Estimated $60,000. Flight attendant did not go on the rescheduled flight. What was your First Day At Work Fail?

Source: https://www.ladbible.com/news/british-airways-emergency-slide-accident-heathrow-320817-20230117