Please try to behave as if you are pleased to see your hosts, dumping your belongings in the guest room and then fucking off out to local attractions makes us feel like a hotel.
If your hostess says: "Is X okay for dinner?" it is intelligent to tell her at the time of asking that you don't like it rather than sitting down at the table with the air of a martyr and then poking it about and complaining with every mouthful that you don't like it. When your hostess (in a desperate attempt to stop the flow of whine) offers to get you something else just say yes and let her fix you something rather than saying "no, no, couldn't put you to the trouble," and then carry on complaining.
If you drink all your host's booze then offer to replace it. Do not say meaningfully: "We've run out of wine you know." We have not run out of wine you slimy twatwaffle, you drank it all you utter bastard 
If you don't like cats don't come and stay with me. I will not shut them outside for the duration of your visit just because you find cats 'creepy' - they live here, you don't, now off you fuck.
If you ask to go grocery shopping with your hostess, and go round piling beer, magazines and costly snacks into the trolley it is really, really rude to not offer to pay for any of it when you get to the check out.
If the house has two bathrooms - one regular and one en-suite off your host's bedroom, it is rude to 'nip in' without asking to use your host's admittedly oversized bathtub with jets when there is a perfectly good shower and bath tub available in the normal bathroom. Your host does not appreciate not being able to get into his own bathroom to take his medication and your hostess will be seriously peeved to later discover that you used loads of her products while you were in there.
I have now developed a tendency to be unavailable for booking when any of the above make noises about coming to visit us 