Rule #9- all of the above doesn’t matter, you love these ridiculous damn people even as you think they’re each a disaster in their own special way, and they feel the same about you.
Rule #8- everything is competitive and everyone is keeping score- who brought the most expensive gift? Who gained 10 lbs? who had the most obnoxiously smarmy Christmas letter about their perfect kid? And who’s letter was suspiciously short to elide a bad year?