Christmas spirit takes a sharp left turn when a sister spends years showing up for every family ritual, gets told that inconvenience is just the price of community, and finally decides the price is way too high for what she actually receives.  

This setup is basically a frequent flyer program for one. The older sister treats birthdays and Christmas like mandatory pilgrimages, and the narrator has been the reliable attendee, rearranging life to keep the tradition train running. Meanwhile, when something matters to her, like a thesis defense years in the making, the response is suddenly too busy. Family, in this system, means one person bending so the other can feel like the director of a meaningful ensemble cast. The moment that pattern gets named, out comes the invoice, a long list of favors dating back to 2009, as if support expires the second anyone questions the terms.  

The line inconvenience is the price of community sounds deep until you notice who keeps paying. Funny how community always becomes a moral lesson when the person doing the lecturing is not the one exhausted. Blocking a sibling for pointing out the imbalance just confirms it. What is being offered here is not shared tradition, it is attendance.