The dish you don't want at the dinner table
Thanksgiving is one of a handful of holidays (along with Easter and Christmas) where you have the opportunity to invite assorted family and friends over for a large meal. Some of us do it because we really want to see all these folks, while others do it more out of a sense of some type of cultural/traditional obligation.
Whatever your motivation might be, there are certain conversational topics you may want to steer clear of in order to keep holiday harmony intact. (And, to keep the pumpkin pie from flying, too.)