In-laws.
Or, more to the point, the way your lover/spouse/SO/whatever you call them reacts to their family.
(obligatory note I put on all posts relating to my wife's family: they are perfectly nice people, I don't really hate them but they drive me crazy, mostly because I'm a crusty old misanthrope)
My wife, bless his dear heart, becomes a completely different person in the presence of his family. He becomes this over accomodating, spineless Stepford wife. His brain takes leave of his skull and things come out of his mouth that he should NEVER, EVER, under ANY circumstance say. Things like:
"You can all stay at our house."
*sound of screeching tires*
Stop this ride, I want off. And I want off NOW.
Not only does he say stupid things like the above referenced, he does so without my knowledge. So he exclaims the above phrase and then, sheepishly and with much remorse, slowly tries to sneak this pill of info into normal conversation, hoping I won't notice and just swallow it down.
Then, when I spit it back in his face (along with a string of very colorful language) he acts shocked. SHOCKED, I tell you, that I'm reacting how I always react when someone not only plans to disrupt my routine but then tries to sneak it by me and then LIES and says "oh, I didn't think, I didn't do it on purpose, really".
So now, much to my HORROR, I'm faced with housing SEVEN houseguests. Yes, you read that right, SEVEN. Mind you, we only have two spare beds (and I mean real beds, not fold-away beds or that kind of thing) . And, my house is just now drying out from the leaking roof, so one room (we have three spare rooms) is in such a state that no living thing should inhabit it. We do have one fold out (couch) bed but it's really not much more than a prison mattress (it's a fold away bed in an Ikea loveseat, so it's not roomy or really that nice) and our futon is in such sad shape I wouldn't offer it to a stray dog. But apparently none of this matters to my wife. All that matters is he accomodate them so he can feed his father's "The Waltons" fantasy, where the whole clan constantly bask in the loving glow of one another's company.
It's a good thing I love my wife or I'd squeeze his neck until his cute little head pops right off. I swear.