What was your worst vacation ever and why?

Ft. Myers Beach 1998
My H and my sister decided to attend the same medical conference. We all met there with my sister’s H, me, and our combined 7 kids, (6 boys, one girl, ages 2-9). Our kids had never seen the ocean before, so we thought we would hang out at the beach during the conference. My other sister (single, childless) came along to help watch the kids.
My oldest son broke his arm 2 days before we left. The condo we rented was grungy/smelly–but none open to move to. My boys all got sick with diarrhea/vomiting after two days. It rained–big lightening storms, so little beach time. We tried to go on a nature walk at a park one day. After only a few yards we were covered with mosquitos. (I slapped my leg and hit dozens of them, blood was running down my leg. It was like a horror movie.) Ran back to the van as fast as possible. Took the kids to the pool one day. My 4yo son made a really loud embarrassing observation about a woman’s anatomy, and when I gave him the “omg shut up now” look, he repeated himself louder, pointing at the woman. Auntie (my single sister) was cranky and mean the whole time.(Can you blame her?) General disagreements/bickering over what to eat/where to go/who is watching kids, keeping not-sick cousins away from my sick kids/general chaos. S threw up on the plane on the way back. I have a photo of my 4 kids (including my son with his broken arm) digging in the sand on the beach. Dark clouds in the background. Water looks gray. All kids are scowling, looking ill. A good time was had by no one. And we never went back to Florida again.