I'm an adult in my late 20s (with mild symptoms of OCD, I think). I'm obsessed with keeping the house in order (to a tee) and keeping everyone around me amicable. I can't seem to be able to do both when my parents come over to visit.
The need for the house to be in perfect order probably stems from my childhood spent at my parents' - from their lack of order. Everything would lie scattered everywhere. All my attempts at straightening up the place were met with resistance. And since I was "just a kid", I couldn't do much.
Now that i have and run my own house, I pride myself in keeping it in perfect order. And it's all thrown away when my parents come to visit. There are somethings which they don't even see as dirtying/improper - like eating/cooking without spilling - they cant help it or its just not in their nature. Its really hard to do, but I let those slide; I don't nitpick. But I can't even bring up the things that are deal breakers without immensely upsetting them. Like, they'll handle spices with wet, dripping hands. They'll put those wet dripping hands into cookie jars etc. The risk of spoiling and fungus growth is real here! The bottom of their plates always have food sticking to them and they'll keep them on sofas and chairs.. upholstery and leather aren't easy to clean! All their stuff is on the dining table even though they have a room to themselves... The list goes on.
If I bring it up and tell them not to do this stuff, they'll sulk and sulk for a whole day. I don't know if they feel like they can't be themselves in my house, or that they're not welcome here.. But after the initial few times of frayed tempers, I've been careful to tell them politely. I'm the one who always tries to cheer them up later too! They still don't seem to like me saying anything at all! I really don't want to play the "my house, my rules" card, although that's how I feel! How do I get my point across without making them feel unwelcome in my house?
P.S. As I was writing this question, I felt like I am handling childlike behavior combined with adult ego!