GiddyOnZackHunt,
Posts like yours do make me wonder(not critically, genuinely curious) why did you go(and stay) at all? I understand when some posters go for the sake of their DHs, but you say they had nothing in common and - I suppose -didn't miss each other. Doesn't sound like FIL enjoyed your visits either! Why did you go, did he insist you come and visit out of some sense of decorum?
I'm definitely not going to visit anyone any more just to tick the box, or if it's desperately uncomfortable for me, if it's ever needed for the sake of DH/DC, I'll just do everything possible to dispatch them by themselves..
My worst stay somewhere was actually not with anyone, but in a one bedroom apartment my mother bought in a Southern European country, and invited us(6 of us, eldest late teens, youngest toddler, studio apartment, +35-40 outside every day, one bathroom) to use it as a holiday place. She initially planned to come and stay there herself at the same time, but then realised it would have been unworkable, space-wise. Due to the heat/space/boredom/childcare issues it turned out to be a holiday from hell, my DH and I were seriously thinking of breaking up by the end of it, even though the apartment had a balcony with the view of the sea and was 7 min walk from the (awful) beach. We were soooo frazzled by the end of our stay, if we could, we would have left earlier. Had my mother been there, it would have been a post about how we stayed with DM and how horrendous it all was, and how we were never going back 
But actually her presence would have been incidental, might have made some things worse, some things better, but it was just about finding ourselves in really testing circumstances (while looking forward for some R&R). My DM couldn't praise the flat/location high enough as a holiday place, which we realised was true for 1 or two people, totally, but not for a family with kids of different ages and interests at the height of summer in a hot country.
Lots of posts on here are similar in the sense that people are going to see family in their time off, so there might be some subconscious expectation of a break, but actually end up feeling more tired by the end of the 'holiday' due to the constraints of living under someone else's rules and plain discomfort of small/hard beds, shared bathrooms, paper thin walls etc.
But it's funny to discuss idiosyncrasies of one's family :). I'm looking forward to being a MIL and if SILs and DILs want to stay, they would be allowed a free run of the house, I'm very laid-back, but I'm sure they would find things to amuse/puzzle them. This thread actually helps in identifying and trying to prevent potential discomforts experienced by family staying round.