I may be approaching one after this Christmas. The trick is that if things go the way I'm afraid they will, it will be such a gradual process that I might have a very hard time resisting the trend without looking overly sensitive and like the resident family killjoy.
Basically, I live on one coast, my brother lives on the other, and my sister and parents live in the middle of the country. My mom's family also mostly lives in the same area my parents live in, so family gatherings when I was growing up were always very large. My dad's family is not close, so we only spent a handful of holidays with them. My personal ideal is to spend holidays with my parents where they live, because that way I get to see my aunts and uncles and cousins, and because for me, that's a traditional holiday (no matter what we actually end up doing).
Last year, my parents and sister decided to visit my brother for Christmas, because he lives in a part of the country that is pretty spectacular in the winter. I decided to visit as well, because I couldn't resist the chance to see all of my immediate family at once, and because my parents offered to pay for my and my husband's airfare as our Christmas presents. It was fun, but the travel was difficult (they live in a small town, and the winter weather made a long and challenging trip that much more complex), and we basically had a SIL Family Christmas. Despite the fact that my family outnumbered hers (even with her parents, who live in the area), her family's traditions were the ones that held sway.
As a sometimes thing, I wouldn't mind all of that. It was fun, but at the same time, I don't want to do it every year. I want to celebrate my own family's traditions, I want to have actual Christmas presents and not just airfare (and I can't afford the airfare on my own), and I want to see my extended family. On top of that, I do have a husband and his family and his traditions to consider, and Christmas is the one holiday that both of our families celebrate (he is not American, so Thanksgiving is pretty much whatever I want to do).
But it's beginning to sound like my brother and SIL expect us to visit them every year. They don't like the weather where my parents live for Christmas (understandable, since it's sometimes actually hot), and now that they have a baby daughter, I'm sure travel will be that much more difficult for them. But I swear, if it starts to become the My Family "thing" to visit my brother and have a SIL Family Christmas, that will become my hill to die on. And whether I choose to participate in that style Christmas or not, I will resent the heck out of everyone for making me choose between the traditions I value and seeing my actual family.
Of course, you have to add in the fact that my brother and I both moved away from my parents' city 4 years ago, and I have visited him 4 times. He's never once visited me. My sister has never visited me. My parents do visit, but not as often as they visit my brother. I know the reason is because I have a one-bedroom apartment, so visiting me is a lot more expensive than visiting my brother (he owns a house with extra bedrooms). But no matter how logical that argument, it still hurts that because I have less money than my brother (basically), I'm always the one who has to travel. Having to give up my holiday traditions on top of that is just too much.