EMILY: Your father and I are going out of town the next day and we’ll be gone all of December, including Christmas, so it’s the last chance for the family to be together for the rest of the year.
Emily and Richard supposedly throw a dinner party two weeks before Christmas every year, before they leave for their winter vacation. They seem to have cancelled it this year, leaving for their vacation straight after Thanksgiving, so perhaps they are in bad moods over the Yale incident as well.
It seemed as this annual never-to-be-changed tradition was cancelled the year before as well, because Richard was in a mood over his forced retirement, so perhaps this tradition isn’t a tradition any more? Richard had to be rushed to hospital during the Christmas party of 2000, and it’s possible that put them off holding another one.
The Annotated Gilmore Girls 