Gravy is the single most important thing on thanksgiving, and it's not even close

If everything at Thanksgiving is mediocre, but 1 thing, you want that one really good thing to be the gravy. Great gravy can save a bad turkey, potatoes, or stuffing. A bad gravy can ruin the turkey, potatoes, or stuffing, then what are you gonna do eat dry turkey? Great turkey is great turkey, but the quality of the turkey doesn't effect the quality of the potatoes.

Edit: yes, in a perfect world everything would be made perfectly and wouldn't need fixing with gravy. But for a gathering of 2 dozen people not everyone can make an immaculate dish. As I said, if your aunts bring sub par dishes good gravy is important, if your aunts bring sub par gravy then you don't have that option.