What was your worst vacation ever and why?

Renting a shore house for a week many years ago. We asked my H’s family if they wanted to go in on a house - answer was no. This was typical - no, but then show up and want to spend “a few nights”. Nope, too crowded - if you want to stay, chip in and we’ll get a bigger place.
So it rains the entire week. His brother, wife and 3 kids want to come down and stay in our place - I say no. So they come down and rent a campsite in the area, which floods and they come to our place and basically blame me. At one point during the week there were 12 people sitting in our place (his parents, siblings just stopping by!!) It was a nightmare.