We were developing software for an office in a timezone several hours different from our own. We flew there the weekend before the Monday launch, did several te

We were developing software for an office in a timezone several hours different from our own. We flew there the weekend before the Monday launch, did several tests over the weekend and everything looked good. Monday morning, minutes before go live we do a couple more tests with staff and discover a critical timezone bug that if not fixed, we cannot go live. Even if our developers were able to quickly turn around a fix and skip formal QA, it still would be ~30mins before everything was updated and another 30 for us to do local tests on site... So we went around and changed the timezone on every computer in the office. The day was saved, devs fixed the bug during their day, our night and we fixed the timezones the following day.