I'm glad we aren't the only ones these things happen to...I guess I have 3 "bad" memories from 2 different trips.
In 2003, it was only my 2nd trip as an adult and we weren't quite as well-versed as we are now. I'm usually pretty OK, but once in awhile I must get hypoglycemic or something because I need food/drink and I need it NOW (it is rare, but when it happens, there is no doing anything else until I get what I need!). We were in EPCOT sort of in between Future World and World Showcase. It was August (need I say more?). I *had* to have a snack, like immediately. We walked ALL THE WAY over to the Odyssey restaurant...um, hello! It isn't open anymore!?! I guess we had skipped that side of the park on our previous trip and DH didn't realize it was closed. I was literally in tears by the time we made it to a snack cart for fries and a soda. I'm sure I looked like a lunatic...I carry a snack with me at all times now.
On that same trip, at AK, (still August, still hot)...DH was running from Pizzafari to Kilimanjaro Safari (for some reason, I still don't remember why). He dropped our camera (a 35 mm), the back sprung open, and our roll of film was ruined. Thankfully the camera didn't break...we got a digital camera before the next trip...
In 2005, we took a big family trip for Christmas. On the drive down, my nephew was sick (as in throwing up). We all sort of knew it would make the rounds, but we held out hope for the best. My parents and sister got it early in the trip (first day or so). My DD got it sort of in the middle...she was about 4 years old and was sleeping with me. I woke up in the night with her throwing up...all over me. Yes, my kid threw up and a little bit got in my mouth.

Thankfully, it only lasted about a day for her. I had the good fortune of having it on the drive home. I've gotten sick at every northbound rest-area between Orlando and the Georgia border on I-75.
Funny though, we can sort of laugh about those things now, even if they were making us crazy at the time!