29. International wedding
The bride asked all of her bridesmaids to visit her country for the wedding, which would include having to book an international flight, find lodging, etc.
It was only halfway through the actual wedding itself that we found out she was having four weddings in four different locations and that she was visiting each of our respective countries to have one. She just really needed all the bridesmaids to fly in for this one because of reasons. She wound up cheating on her husband and getting divorced in under a year.
Absolute waste of time and money.