Today we found out about the traditional Christmas Dinner that happened at my great-uncle Jack's house.
He and Aunt Catherine had six children (which I'm sure chaffed my grandmother's zero-population growth sensibilities). They would enjoy tacos for their holiday dinner. It required so much prep work (browning, dicing, grating...) that they wouldn't have tacos very often, so it was a special meal for a special occasion in their household.
At least that's how the family lore tells it.