I'm the person who can handle being around people for only so long before I break down and have to find somewhere to be alone. I like to think of that time as my re-charging period. I get so completely drained when I'm constantly around people...in just about any scenario. From family, to close friends, to complete strangers--its a little too much most of the time.
John's the only person I can actually not have to retreat from-but even with him, if we are together all weekend, I may have to sneak off for 20 minutes and just breathe.
I'm guessing this may have something to do with being an only child. Or maybe not at all. I guess john's the exception because we can just sit there, or lay there, or whatever and not have to say anything but we still are able to communicate.