1. Port-o-Potty in Baghdad. Summer was BRUTAL.
2. Wooden outhouse shitter in Pohang, Korea at Marine Expeditionary Camp - Pohang (MECP). Wooden outhouse with 55 gallon drum underneath to catch the goodies. Some wannabe engineer Marine decided that a toilet seat screwed to the hole was a good idea (and it probably was). Unfortunately, some logistician (possibly a Russian given the news of today) didn't think to contract a shit sucker until after we got there. After just a few days, the shit was piled up above the toilet seat. Once it got to that point, I was not utilizing the facilities. I found it curious how someone did it at that point, though. It was obviously a hovering aerial bombardment, but holy cow that would be brutal.
3. Guantamano Bay in the early 90's. The Air Force brought in portable shitters and showers and they were not climate controlled. They rolled the window flaps up on the tents and the toilets were elevated. It wasn't that it was a bad place to shit, but you kind of felt like you were on stage taking care of business as people were walking by outside and could see you through the window flaps.
Korea was in the late 80's. My understanding is that MECP has been built up quite a bit since then. I'm fairly certain that they have indoor plumbing now, but back then it wasn't too posh.
I have taken a shit in which most people would consider undesirable places, but the relief far outweighed the bad atmosphere.