I think that's just family though. Cram a bunch of people that are only connected by blood or marriage together into a house once a year when you spend the rest of the year actively avoiding each other and it's sure to be awkward. It's hard to avoid everyone all at once unless you lock yourself into a far removed closet. Which actually, my cousin Gary did that every year while I was growing up, he'd hide in a bedroom.
Now though, since I'm married, we've had to incorporate the husband's family and mine together. Both of our families are weird, but in totally different ways. His parents are in their 60s, upper middle class, straight up Leave It To Beaver types. My parents are in their 50s, they came of age in the very stoned 70s and are pretty spacey and boozy.
Long story short now we're gathering with my husbands family minus my mother's brother and his family.