What are some stories of things interns have done to really screw up?

Based on the most engaging WSO threads, here are some standout intern screw-up stories:

1. Brexit Morning Disaster: An intern went out for happy hour with their team the night before Brexit, got extremely drunk, threw up on the HR manager, and had to be taken home by an MD. The next morning, they overslept and showed up at 11 AM—on one of the most critical days in the financial markets.

2. Currency Symbol Catastrophe: An intern prepared a pitch book for a prospective client but mistakenly used Philippine Peso symbols throughout the presentation. The client interrupted on the first slide, asking, "What the f***?" The story got back to the client in Europe, and the intern was blacklisted not only from the bank but also from every bank the MD had connections with.

3. Payroll Jackpot: A group of interns managed to make over $80,000 in one summer due to a major payroll error. While not a "screw-up" on their part, it was a wild situation that could have had serious consequences if discovered.

4. Model Mishap: An intern misunderstood the requirements for a financial model, didn’t clarify details, and failed to ask questions. During a client call, the numbers in the model made no sense, leading to an embarrassing situation where the MD had to reschedule the call to fix the errors.

These stories highlight the importance of professionalism, attention to detail, and knowing your limits as an intern.

Sources: Most Badass Intern Story?, How to recover from early mistakes in my SA?, Most Badass Intern Story?, Summer 2017 Investment Banking Interns - Do's and Don'ts List, Advice from an ex-IB MD - DON'T make these mistakes