(I'm sorry about the title, I couldn't think of anything better)
Recently there's been several threads that have involved social situations and people not being involved in them during the whole time (like the falling asleep in the car thing). The idea that you should be sociable during the whole time is a bit surprising to me, in my country being antisocial isn't really seen as something bad (very sociable people are suspicious). I was wondering if it would be always rude or if there are some exceptions.
I spent last weekend with my boyfriend and his friends (three men, three women) at a country place owned by the parents of one of the friends (it was a wonderful place with sheep and chickens and lots of antiques), we were there from Saturday morning to Sunday evening, so quite a long time. Most of the time people were together, eating, cooking and looking at the sheep. Some people might have drifted a little but during the main social events (mainly meals) everyone was present. Apart from one event, where I didn't take part.
The place was by a lake and as they other people love saunas and swimming they spent couple of hours in the evening doing that. I stayed at the house and read a book. My reason was that I'm rather shy and uncertain about my looks, I don't want to be naked in front of a group of people I don't know that well (actually it's easier to be naked among strangers, like at the pool) and I don't really enjoy saunas that much, especially small saunas where you have to sit very close to the other naked people. They also swam naked, they didn't even bring swimming suits with them (and the place is private enough so that it doesn't bother the neighbours). I don't enjoy that much swimming either, so I much prefered sitting on the porch reading. I could have sat on the beach also, but I didn't really want to look at the naked people (I seem very repressed

). They didn't seem to mind and apparently there have been people who won't go to sauna with them (like an American girl), but I guess that it might have been better if I took part in some way. So if going with them would have been very stressful for me (staying there was stressful enough), what should I have done?