I haven'd made any significant mistake yet, but I have a story of my friend
It was during her internship, and she has terrible phone phobia She was alone in the office at lunch break and the phone rang, once, twice, it didn't stop ringing for a good 20-25 minutes she told me She was stressed but didn't want to answer it Finally a coworker arrives, and she plays innocent "oh, it's ringing" , the coworker picks up, it's the boss who's stuck in the elevator and wants them to go free him cause the help button in the elevator wasn't working
The boss ended up realizing he had the phone number of the help service on top of the help button when the coworker told him on the phone, and the technicians did end up freeing him after an hour